Intraoral appliances with proximity and contact sensing

ABSTRACT

Detection of placement of dental aligners in patient mouth on teeth for indication of wearing compliance. Described herein are apparatuses and methods for detecting wearing, including compliance. In some variations these apparatuses and methods may include a sensor configured to detect deflection of the one or more deflectable structures. In some variations, these apparatuses and methods may include a proximity sensor coupled to the appliance shell and configured to generate sensor data when in proximity with intraoral tissue.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.17/146,465 filed Jan. 11, 2021, titled “INTRAORAL APPLIANCES WITHPROXIMITY AND CONTACT SENSING,” now U.S. Pat. No. 11,304,778, which is acontinuation of U.S. patent application Ser. No. 16/680,393, filed Nov.11, 2019, titled “INTRAORAL APPLIANCES WITH PROXIMITY AND CONTACTSENSING,” now U.S. Pat. No. 10,888,396, which is a continuation of U.S.patent application Ser. No. 15/625,872, filed Jun. 16, 2017, titled“INTRAORAL APPLIANCES WITH SENSING,” now U.S. Pat. No. 10,470,847, whichclaims priority to U.S. Provisional Patent Application No. 62/351,516,filed Jun. 17, 2016, titled “EMBEDDED INTRAORAL SENSING FORPHYSIOLOGICAL MONITORING AND TREATMENT WITH AN ORAL APPLIANCE,” U.S.Provisional Patent Application No. 62/351,391, filed Jun. 17, 2016,titled “ELECTRONIC COMPLIANCE INDICATOR FOR INTRAORAL APPLIANCES,” andU.S. Provisional Patent Application No. 62/483,283, filed Apr. 7, 2017,titled “WIRELESS ELECTRONIC COMPLIANCE INDICATOR, READER CASE AND USERINTERFACE FOR INTRAORAL APPLIANCES.”

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

BACKGROUND

Orthodontic procedures typically involve repositioning a patient's teethto a desired arrangement in order to correct malocclusions and/orimprove aesthetics. To achieve these objectives, orthodontic appliancessuch as braces, shell aligners, and the like can be applied to thepatient's teeth by an orthodontic practitioner. The appliance can beconfigured to exert force on one or more teeth in order to effectdesired tooth movements according to a treatment plan.

During orthodontic treatment with patient-removable appliances, thepractitioner may rely on the patient to comply with the prescribedappliance usage. In some instances, a patient may not wear theorthodontic appliance as prescribed by the practitioner. Extendedremoval of the appliance, for any reason beyond what is recommended, mayinterrupt the treatment plan and lengthen the overall period oftreatment. There is a need for methods and apparatuses that allowmonitoring of the wearing and/or effects of intraoral appliances.Described herein are methods and apparatuses for performing suchmonitoring.

Obstructive sleep apnea (hereinafter “OSA”) is a medical conditioncharacterized by complete or partial blockage of the upper airway duringsleep. The obstruction may be related to relaxation of soft tissues andmuscles in or around the throat (e.g., the soft palate, back of thetongue, tonsils, uvula, and pharynx) during sleep. OSA episodes mayoccur multiple times per night and disrupt the patient's sleep cycle.Suffers of chronic OSA may experience sleep deprivation, excessivedaytime sleepiness, chronic fatigue, headaches, snoring, and hypoxia.

Prior methods and apparatus for monitoring physiological characteristicsof patients with conditions such as sleep disordered breathing can beless than ideal in at least some respects. It would be desirable toprovide systems for monitoring physiological characteristics withoutrequiring sensors placed outside of the intraoral cavity. For example,instead of sensors on the body of a patient, implanted within thepatient, or disposed within the mouth but connected to externalapparatus, it is preferred to have sensors that operate autonomouslywithin the intraoral cavity of the patient. It would be helpful toprovide intraoral appliances comprising embedded intraoral sensors,allowing autonomous monitoring of physiological characteristics ofpatients, thereby providing data useful in the diagnosis of sleepdisorders and other oral- and airway-related disorders.

SUMMARY OF THE DISCLOSURE

Described herein are apparatuses, including devices and systems,including in particular appliances (e.g., orthodontic appliances) andmethods for monitoring an orthodontic appliance, including, but notlimited to monitoring patient compliance with orthodontic treatment.Monitoring may alternatively or additionally include monitoring status,monitoring wear of the appliance, monitoring the geographic/spatiallocation of the appliance, monitoring the environment of the appliance,etc. In some embodiments, an orthodontic appliance includes one or moresensors configured to obtain sensor data; these sensors may includethose that are indicative of patient compliance (e.g., whether thepatient is wearing the appliance). The appliance can include one or moreprocessors operably coupled to the sensor(s) and configured to processthe sensor data so as to generate patient compliance data, thus enablingelectronic monitoring of patient compliance with a prescribed course oforthodontic treatment. Advantageously, the systems, methods, and devicesherein may increase patient compliance and improve treatment efficacy,as well as provide patient data useful to the practitioner for designingand monitoring orthodontic treatments.

A device for monitoring usage of an intraoral appliance may include anappliance shell comprising a plurality of teeth receiving cavities; oneor more sensors operably coupled to the appliance shell and configuredto generate sensor data indicative of appliance usage by a patient; anda processor operably coupled to the one or more sensors and configuredto process the sensor data so as to determine whether the intraoralappliance is being worn on the patient's teeth.

The apparatuses and methods described herein may be configured to detect(“smart detection”) placement of aligners on a tooth or teeth and may beconfigured to differentiate from other, similar, events such as waterimmersion. Also described herein are methods and apparatuses that permitdirect communication with cell phones for activation and retrieving datafrom monitor(s).

As mentioned, the methods and apparatuses described herein may generallybe used with or as part of any monitoring devices for monitoring anorthodontic appliance. For example, described herein are ElectronicCompliance Indicator (ECI) apparatuses that may be configured to recordsensor data from subjects (e.g., patients) wearing or intended/intendingto wear an orthodontic aligner such as a shell aligner. However, itshould be understood that these methods and apparatuses are not limitedto just monitoring compliance and operation on compliance data, but maybe used for any type of data, and these monitoring apparatuses(including ECIs) may also be generically referred to as data loggers orembedded data loggers. Thus, in any of the description and examplesprovided herein, unless the context makes it clear otherwise, when an“ECI” apparatus is described, the apparatus may not be limited tocompliance monitoring. Thus, for any of the description, examples,methods and apparatuses described herein, the term “ECI” should beunderstood to be more broadly referred to as a monitoring apparatus (MA)or performance monitoring apparatus (PMA), and not just an ECI.

For example, in any of these apparatuses, the data may be stored inphysical memory on the monitoring apparatus (e.g., the ECI) and may beretrieved by another device in communication with the monitoringapparatus. Retrieval may be done wirelessly, e.g., using near-fieldcommunication (NFC) and/or Bluetooth (BLE) technologies to use asmartphone or other hand-held device to retrieve the data. Specificallydescribed herein are monitoring apparatuses (including ECI apparatuses)and orthodontic aligners using them that include temperature andcapacitive sensors, a CPU, a NFC communication module, an NFC antenna, aPCB and battery. Also described herein are cases or holders that mayboost and/or relay the signals from the small monitoring apparatus to ahandheld device such as a smartphone; such cases or holders may bereferred to as NFC-BLE enabled Aligner cases.

A monitoring apparatus such as an electronic compliance indicator (ECI)apparatus configured to monitor usage of an intraoral appliance mayinclude a housing enclosing a power source and monitoring circuitry, themonitoring circuitry comprising a processor, a memory, and one or moresensors; a removable mechanical activation interrupt between the powersource and the processor, wherein the mechanical activation interrupthas a first position that breaks a connection between the power sourceand the monitoring circuitry so that no current flows between the powersource and the monitoring circuitry and a second position in which thereis an electrical connection between the monitoring circuitry and thepower source; and an elastomeric overmold encapsulating the housing.

The removable mechanical activation interrupt may comprise a magneticswitch, a removable activation rod, a pin, etc. Any of these apparatusesmay include the dental appliance (e.g., an aligner such as a shellaligner) to which the monitoring apparatus (e.g., ECI) may bepermanently or removably coupled.

In general, any of the monitoring apparatus (e.g., ECI apparatuses) maybe sized to fit against or over one tooth. For example the housing mayhave a maximum diameter of 2 cm or less, 1.5 cm or less, 1.0 cm or less,0.9 cm or less, 0.8 cm or less, 0.7 cm or less, 0.6 cm or less, etc.).The monitoring apparatus housing may generally be thin (e.g., 1.0 cm orless, 0.9 cm or less, 0.8 cm or less, 0.7 cm or less, 0.6 cm or less,0.5 cm or less, 0.4 cm or less, etc.). In any of these apparatuses, themonitoring circuitry may be configured for a wired connection, e.g., mayinclude a plurality of data electrodes external to the housing butencapsulated by the elastic overmold. The apparatus may configured to beconnect to a plurality of metallic/conductive leads that pierce the(e.g., self-healing) overmold material to contact the otherwise coveredcontacts.

Also described herein are methods of activating a monitoring apparatus(such as an electronic compliance indicator or ECI) configured tomonitor an intraoral appliance. For example, a method may include:moving a mechanical activation interrupt of the monitoring apparatusfrom a first position that breaks a connection between a power sourceand a monitoring circuitry of the monitoring apparatus such that nocurrent flows between the power source and the monitoring circuitry to asecond position in which there is an electrical connection between themonitoring circuitry and the power source; inserting the monitoringapparatus, coupled to an orthodontic appliance, into a patient's oralcavity; and recording data from one or more sensors with the monitoringapparatus. Moving the mechanical activation interrupt may comprise:operating a magnetic switch by removing the monitoring apparatus from apackaging having a permanent magnet; inserting or removing an activationrod; and/or inserting or removing a pin. The method may also includecoupling the monitoring apparatus to the orthodontic appliance.Inserting the monitoring apparatus may comprise inserting the monitoringapparatus coupled to a shell aligner. Recording data may compriserecording data from two or more sensors of the monitoring apparatusevery 1 to every 30 minutes (e.g., every approximately 10 minutes).

Also described herein are monitoring apparatuses (e.g., electroniccompliance indicator apparatuses) configured to monitor usage of anintraoral appliance and provide output via a removable wired connection.A monitoring apparatus may include: a housing enclosing a power sourceand monitoring circuitry, the monitoring circuitry comprising aprocessor, a memory, and one or more sensors; a self-healing elastomericovermold encapsulating the housing; a plurality of data electrodesexternal to the housing but encapsulated by the elastic overmold; and anattachment configured to secure the monitoring apparatus to anorthodontic appliance. The apparatus may include the orthodonticappliance (e.g., a shell aligner). Any appropriate self-healing materialmay be used, including an electrically insulating polymeric material.

Also described herein are boosters and/or converters for transferring asignal (such as a NFC signal) from the monitoring apparatus to a signalthat can be received by a smartphone, which typically has a much larger(and poorly matched/difficult to match) antenna for receiving the NFCfrom the monitoring apparatus device. For example, described herein arenear field communication (NFC) to Bluetooth communication (BLE) signalcoupler devices for relaying monitoring data from an orthodonticMonitoring Apparatus (monitoring apparatus, such as an ECI) to ahandheld processor (such as a smartphone). These devices may include: ahousing; a first antenna configured for NFC within the housing; a secondantenna configured for BLE within the housing; a holder on the housingconfigured to hold the monitoring apparatus in alignment with the firstantenna; and NFC to BLE transmission circuitry configured to receivedata from the first antenna and to transmit data from the secondantenna. The holder may comprise a case formed at least partially fromthe housing and configured to hold the monitoring apparatus (or the MAand dental appliance such as an aligner) within the case so that themonitoring apparatus is aligned with the first antenna. The NFC to BLEtransmission circuitry may comprise a power source within the housing.The holder may include an indentation on the housing. The first antennamay comprise a trace antenna or a coil antenna; for example, the firstantenna comprises a toroidal loop antenna having a gap.

Although the apparatuses and methods described herein include numerousexamples of near field communication (NFC), including NFC-to-NFCcommunication, any of the methods and apparatuses described herein maybe used with other types of wireless communication modes, including,without limitation, Wi-Fi, radio (RF, UHF, etc.), infrared (IR),microwave, Bluetooth (including Bluetooth low energy or BLE), magneticfield induction (including NFC), Wimax, Zigbee, ultrasound, etc. Inparticular, the methods and apparatuses described herein may includeapparatuses that convert between these different wireless modes.

Also described herein are methods of relaying monitoring data from anorthodontic Monitoring Apparatus (such as an electronic complianceindicator apparatus) to a handheld processor. For example, a method maycomprise: aligning a monitoring apparatus with a first antenna within ahousing of a near field communication (NFC) to Bluetooth communication(e.g., BLE) signal coupler device; transmitting the monitoring data fromthe monitoring apparatus to the NFC to BLE signal coupler device by NFC;and retransmitting the monitoring data from the NFC to BLE signalcoupler device via a Bluetooth signal to a handheld electronics device.The method may also include inserting the monitoring apparatus into theNFC to BLE signal coupler device, wherein the NFC to BLE signal couplerdevice is configured as a case configured to hold the monitoringapparatus (or MA and a dental appliance to which the monitoringapparatus is coupled). The method may also include receiving theBluetooth signal in the handheld electronics device, wherein thehandheld electronics device comprises a smartphone. The method may alsoinclude modifying the monitoring data before retransmitting the data.Transmitting the monitoring data may comprise receiving the NFC signalcomprising the monitoring data on a first antenna of the NFC to BLEsignal coupler device; alternatively or additionally, retransmitting themonitoring data may comprise transmitting the monitoring data as theBluetooth data via a second antenna of the NFC to BLE signal couplerdevice configured for Bluetooth communication.

Also described herein are improved systems, methods, and apparatus formonitoring physiological characteristics of patients, including from apatient's airway. In many embodiments, an orthodontic appliance isprovided. The orthodontic appliance comprises one or more intraoralsensors embedded within an appliance shell shaped to receive teeth. Insome embodiments, the intraoral sensors comprise a transmitter and areceiver. In some embodiments, the intraoral sensors comprise aplurality of electrodes. The one or more intraoral sensors are coupledto one or more processors. The processors are configured to determine acharacteristic of the patient's intraoral cavity or airway based onmeasurements from the intraoral sensors. In some cases, the measurementsinclude electrical impedance measurements. In some cases, themeasurements include return signals from the patient's intraoral cavityor airway in response to emitted signals from a transmitter. Monitoringthe physiological characteristics of patients using the appliancesdisclosed herein allows more precise diagnosis of patient conditionssuch as OSA. Because the symptoms of diseases such as OSA manifest whenthe patient is unconscious, autonomous electronic monitoring with anintraoral appliance can provide patient data that would otherwise bedifficult or impossible to obtain, thereby facilitating diagnosis andtreatment of the underlying condition. The monitoring systems andmethods disclosed herein can be combined with a treatment apparatus,such as an appliance applying tooth-moving forces or an appliance forincreasing airway clearance in the treatment of OSA.

In one aspect, an apparatus for monitoring a physiologicalcharacteristic of a patient is provided. The apparatus comprises anintraoral appliance shaped to receive the patient's teeth. The appliancecomprises a plurality of electrodes. The electrodes are positioned tomake electrical contact with the patient's intraoral cavity when theintraoral appliance is worn by the patient. The appliance furthercomprises one or more processors configured to use the electrodes tomeasure an electrical impedance. The processor uses the measuredelectrical impedance to determine a physiological characteristic of thepatient.

In another aspect, an apparatus for monitoring a characteristic of apatient's intraoral cavity or airway is provided. The apparatuscomprises an intraoral appliance shaped to receive the patient's teethand includes a transmitter and a receiver. The appliance may furthercomprise one or more processors configured to cause the transmitter toemit a signal within the patient's intraoral cavity; measure a signalreturning from the patient's intraoral cavity or airway in response tothe emitted signal using the receiver; and determine, based on themeasured signal, the characteristic of the patient's intraoral cavity orairway.

Other objects and features of the present invention will become apparentby a review of the specification, claims, and appended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1A illustrates an example of a tooth repositioning appliance.

FIGS. 1B-1D shows an example of a tooth repositioning system.

FIG. 2 illustrates a method of orthodontic treatment using a pluralityof appliances.

FIG. 3A schematically illustrates an example of a monitoring apparatus(shown as an ECI device).

FIG. 3B schematically illustrates a system including any of theintraoral appliances with one or more sensors as described herein, anddigital scan data of the appliance and/or patient's teeth. An analysisengine (which may be part of the intraoral appliance or separate fromthe intraoral appliance) may integrate the distal information and thesensor information, and may relate the specific sensor information tothe patient's teeth using the digital scan data.

FIG. 4A illustrates an example of an intraoral appliance including anintegrated monitoring device.

FIG. 4B is a cross-sectional view of the appliance of FIG. 4A.

FIG. 5 illustrates an example of a monitoring system including a firstappliance and a second appliance.

FIG. 6A illustrates an example of a system including an intraoralappliance and an attachment device mounted on a tooth.

FIG. 6B shows an example of a system including an intraoral applianceand an attachment device mounted on a tooth.

FIGS. 7A and 7B illustrate an example of a monitoring device with adeflectable structure.

FIG. 7C shows an example of a monitoring device with a deflectablestructure.

FIG. 7D illustrates an exemplary method for fabricating an intraoralappliance with a deflectable structure.

FIG. 8A illustrates an example of an intraoral appliance including acapacitive sensor.

FIG. 8B illustrates an example of a monitoring device integrated into anintraoral appliance.

FIG. 8C illustrates an example of an intraoral appliance in which themajority of the aligner surface comprises a capacitive touch-sensormaterial.

FIG. 8D illustrates an enlarged view, showing the grid pattern of thecapacitive touch sensor that is distributed across the surface of theintraoral appliance of FIG. 8C.

FIG. 9 illustrates an example of a monitoring system for detectingproximity between the patient's jaws.

FIG. 10A shows an example of a monitoring device utilizing opticalsensing.

FIG. 10B illustrates an example of a monitoring device using opticalsensing.

FIG. 10C illustrates an example of a monitoring device using opticalsensing.

FIGS. 11A and 11B illustrate operation of an example of a monitoringdevice using optical sensing.

FIGS. 11C and 11D illustrate an example of a monitoring device usingoptical sensing.

FIGS. 12A and 12B illustrate an example of a monitoring device usingmagnetic sensing.

FIG. 12C shows an example of a monitoring device using magnetic sensing.

FIG. 13A illustrates an example of a monitoring device using magneticsensing.

FIG. 13B illustrates an example of a monitoring device using magneticsensing.

FIG. 13C shows an example of a monitoring device using magnetic sensing.

FIG. 14A illustrates an example of a monitoring device using a pluralityof magnets.

FIG. 14B is a cross-sectional view of the device of FIG. 14A.

FIG. 15 illustrates an example of a monitoring device configured tomeasure force and/or pressure between an intraoral appliance and thepatient's teeth.

FIG. 16A illustrates an example of a monitoring device configured tomeasure force and/or pressure between an intraoral appliance and one ormore attachment devices on a patient's teeth.

FIG. 16B is a cross-sectional view of the device of FIG. 16A.

FIG. 16C is an example of an intraoral device configured to measuremechanical impedance of a tooth or teeth.

FIG. 16D graphically illustrates the detection of acceleration over timeat a particular tooth (or an aligner portion corresponding to aparticular tooth). FIG. 16E graphically illustrates the detection offorce over time at the same tooth (or aligner region) for whichacceleration was determined as shown in FIG. 16D. An intraoral deviceconfigured to measure mechanical impedance such as the apparatus shownin FIG. 16C may correlate the acceleration over time and the force overtime to estimate mechanical impedance for the tooth.

FIG. 16F shows a portion of an intraoral appliance configured to measuremechanical impedance. In this example, one or more motion sensors (e.g.,accelerometers) may be coupled to the tooth (as part of the attachment,as shown) and may communicate with electronic components on theintraoral appliance (e.g., memory, processor, power supply, wirelesscommunications, etc.). The apparatus may also include or may be used inconjunction with a mechanical actuator to provide a known (or measured)perturbing vibration, and the processor may use the known force inputwith the output from the accelerometer to determine mechanical impedancefor the tooth/teeth.

FIG. 17A shows an example of a monitoring device including a gas flowsensor.

FIG. 17B illustrates an example of a monitoring device including a gasflow sensor.

FIG. 17C shows an example of a monitoring device including a gas flowsensor.

FIG. 18 illustrates an example of a monitoring device using motionsensing.

FIG. 19 illustrates an example of a method for monitoring usage of anintraoral appliance.

FIGS. 20A through 20D illustrate an exemplary method for fabricating anintraoral appliance with an integrated monitoring device.

FIGS. 21A through 21C illustrate an example of a method for fabricatingan intraoral appliance with an integrated monitoring device.

FIG. 22 is a simplified block diagram of an example of a data processingsystem.

FIG. 23 illustrates an example of a monitoring device.

FIG. 24 illustrates one example of coupling an ECI apparatus to analigner.

FIG. 25 shows an exemplary prototype of an ECI apparatus coupled to analigner.

FIG. 26 graphically illustrates the use of a capacitance sensor todetect when an aligner is being worn by a user, and/or is submerged in afluid (e.g., water).

FIG. 27 graphically illustrates mutual capacitance measurements (onleft) and self-capacitance measurements (on right).

FIG. 28 shows an example an ECI apparatus having a pair of capacitiveelectrodes.

FIG. 29A shows an enlarged view of the sensing electrodes on an ECIapparatus.

FIG. 29B illustrates the use of capacitive signals from differentsensing electrodes to distinguish wearing of an appliance including anECI apparatus as described.

FIG. 30A shows an example of an ECI apparatus including a pair of guardelectrodes;

FIG. 30B illustrates the complex impedance of an ECI apparatus such asthat shown in FIG. 30A when submerged in water; FIG. 30C is an exampleof an ECI apparatus including capacitance-sensing electrodes positionedat the end of the aligner appliance. FIG. 30D illustrates theinterpretation of the capacitance-sensing electrode to distinguish falsepositives when determining if an appliance having an ECI apparatus suchas that shown in FIG. 30A is being worn.

FIGS. 31A-31D illustrate views of one variation of an aligner caseconfigured as an intermediate device for coupling a near-filed signal(NFC) from an ECI apparatus for output as a Bluetooth signal to a phone.FIG. 31A is a top view with the case cover open. FIG. 31B shows a backview of the case of FIG. 31A, and FIG. 31C is a side view of the case ofFIG. 31A. FIG. 31D is a top view of a prototype of the case shown inFIG. 31A.

FIG. 32 illustrates one example of a system for transmitting datadirectly from an ECI to a smartphone.

FIGS. 33A-33C illustrate an example of a system for transmitting datadirectly from an ECI to a smartphone using a holder/clip tool to holdthe ECI in alignment with the antenna of the phone.

FIGS. 34A and 34B illustrate a trace antenna and the use of a traceantenna to read data from an ECI, respectively. FIG. 34B showsalternative variations of antennas on the aligner.

FIGS. 35A and 35B illustrate a coil antenna and the use of a coilantenna as part of a data reader to read data from an ECI, respectively.

FIG. 36A shows a schematic of a circuit diagram for an NFC couplercoupling between an ECI apparatus and a smartphone. FIG. 36B illustratesan example of a toroid loop antenna with a gap in the ferrite core thatmay be used as part of an NFC coupler, such as illustrated in FIG. 36A,for example. FIG. 36C illustrate overall system coupling between NFCantennas.

FIGS. 37A and 37B illustrate, schematically, an NFC coupling device.

FIG. 38 illustrates a prototype of an NFC coupling device such as theone shown in FIG. 37A.

FIG. 39 is an exemplary circuit diagram of an NFC coupling device.

FIG. 40 is an example of a user interface for an application programthat may coordinate data transfer and/or analysis and/or compliancemonitoring.

FIG. 41 is a flow diagram of a communications protocol that may be partof an application program.

FIG. 42 is a flow diagram for a coordinating near field communicationbetween a smartphone and an ECI apparatus.

FIG. 43 is a flow diagram for data processing using an applicationprogram processing EIC data.

FIG. 44 is a flow diagram schematically illustrating operational statesof an ECI device.

FIG. 45 is a flow chart illustrating the control of communications by areceiving processor (e.g., smartphone) communicating with an ECI device.

FIG. 46 is an example of a process chart for a data processingcomponent/manager.

FIG. 47 illustrates an impedance model of a patient's airway.

FIG. 48A illustrates the variation of patient airway width for differentMallampati scores, and FIG. 48B illustrates the corresponding variationof airway resistance as a function of Mallampati score.

FIG. 49A illustrates a patient's intraoral cavity in conjunction withpoints from which sensors such as electrodes can be placed to measurecharacteristics of the intraoral cavity and airway.

FIG. 49B illustrates alternative positions in which sensors such aselectrodes can be placed to measure characteristics of the intraoralcavity and airway.

FIG. 50A illustrates an appliance wearable over a patient's teethcomprising sensors positioned at diametrically opposed points in apatient's intraoral cavity.

FIG. 50B illustrates an appliance wearable over a patient's teethcomprising sensors positioned in close proximity to each other.

FIG. 50C illustrates an interior of an appliance with an embeddedmeasurement system comprising drive electronics and sensors.

FIG. 50D illustrates examples of alternative, extended positions forsensors and drive electronics.

FIG. 50E illustrates an appliance comprising an upper shell to fit apatient's upper teeth and a lower shell to fit the patient's lowerteeth, each shell comprising an sensor.

FIG. 50F illustrates an appliance configured to measure impedancebetween electrodes on opposite sides of the appliance shell.

FIG. 50G illustrates an appliance with respective sensors on upper andlower shells, in which the sensors are inductively coupled.

FIG. 51A illustrates a block diagram of a signal chain for performingimpedance measurements with the appliances disclosed herein.

FIG. 51B shows a schematic diagram of an oral appliance comprising aplurality of electrodes for measuring the impedance of a system such asthe intraoral cavity or airway of a patient.

FIG. 52 illustrates a method for monitoring a physiologicalcharacteristic of a patient using an appliance as disclosed herein.

FIG. 53 illustrates a method for monitoring a characteristic of apatient's intraoral cavity or airway.

FIG. 54 illustrates a method of manufacturing an appliance comprisingsensors and control electronics.

FIG. 55 illustrates exemplary rotational velocity data collected with agyroscopic accelerometer coupled to the maxilla of a patient.

DETAILED DESCRIPTION

The monitoring apparatuses described herein may generally includeElectronic Compliance Indicators (ECIs). An ECI may record sensor datafrom a subject wearing one or more dental appliances, such asdental/orthodontic aligners, including shell aligners. Data recorded bythe ECI may be stored in physical memory on the ECI and may be retrievedby another device. In particular, the data described may be retrieved bya hand held electronics communication device such as a smartphone,tablet, or the like. The handheld electronics device may include a userinterface to augment communication between the ECI and the device, andmay provide feedback to the user (e.g., patient) and/or technician,physician, dentist, orthodontist, or other medical/dental practitioner.Once transmitted to the handheld device, the data may be processed (orfurther processed) and/or passed on to a remote processor, memory and/orserver.

In particular, described herein are apparatuses for monitoring,including ECIs, that are very small and therefore use a relay, such asan appliance case or holder configured to operate as a relay. Forexample, described herein are apparatuses that use both NFC and BLEcommunication to transmit data between an ECI and a handheld electronicdevice (e.g., smartphone). Using NFC and BLE technologies may allow asmartphone to retrieve the data even from a very small ECI that includesonly a small antenna, with a reasonably high accuracy and low power.

The apparatuses and methods described herein for monitoring treatmentwith removable intraoral appliances may generate sensor data related tousage of an intraoral appliance. The sensor data can be processed andanalyzed to determine whether the patient is wearing the appliance inaccordance with a prescribed treatment plan. Advantageously, theapparatuses and methods described herein provide an integratedelectronic sensing and logging system capable of generating morereliable and accurate patient compliance data, which may be used by thetreating practitioner to track patient behavior and improve treatmentefficacy. Additionally, the monitoring apparatuses described herein mayprovide high value sensing data useful for appliance design. In someembodiments, the sensing data provided by the monitoring apparatusesdescribed herein may be used as feedback to modify parameters of anongoing orthodontic treatment, also known as adaptive closed-looptreatment planning.

The ECI apparatuses described herein may detect when the device is wornon a subject's tooth/teeth using any appropriate method, including oneor more of those described herein. For example, an apparatuses formonitoring usage of an intraoral appliance (an ECI) may include one ormore deflectable structures formed with or coupled to the intraoralappliance. The deflectable structure(s) can be shaped to be deflectedwhen the intraoral appliance is worn on a patient's teeth. The devicecan comprise a sensor configured to generate sensor data indicative ofdeflection of the deflectable structure(s). Optionally, the device cancomprise a processor operably coupled to the sensor and configured toprocess the sensor data so as to determine whether the intraoralappliance is being worn.

The intraoral appliance may comprise an appliance shell including aplurality of teeth receiving cavities. The deflectable structure(s) canbe located near a tooth receiving cavity of the plurality of teethreceiving cavities so as to be deflected outward when a tooth ispositioned within the tooth receiving cavity. The deflectablestructure(s) can be formed in a wall of the tooth receiving cavity. Thedeflectable structure(s) can be deflected outward by at least 25 μm whenthe tooth is positioned within the tooth receiving cavity.

The deflectable structure(s) may comprise a deflected state when theintraoral appliance is being worn and a resting state when the intraoralappliance is not being worn, and the deflectable structure(s) interactwith the sensor when in the deflected state. The sensor can comprise amechanical switch and the deflectable structure(s) can engage themechanical switch when in the deflected state. The sensor can comprisean optical switch and the deflectable structure(s) can activate theoptical switch when in the deflected state.

The deflectable structure(s) may comprise a cantilever, dimple,concavity, flap, protrusion, or pop-out structure.

The apparatuses may further comprise a communication unit operablycoupled to the sensor and configured to transmit one or more of thesensor data or the processed sensor data to a remote device. The sensormay be integrated with the intraoral appliance or coupled to a tooth.The processor may be integrated with the intraoral appliance or coupledto a tooth. Alternatively or additionally, the processor may be locatedexternal to the patient's intraoral cavity.

Any of the devices for monitoring usage of an intraoral appliance maycomprise an appliance shell comprising a plurality of teeth receivingcavities and one or more proximity sensors operably coupled to theappliance shell and configured to generate sensor data when in proximitywith intraoral tissue. The device can comprise a processor operablycoupled to the one or more proximity sensors and configured to processthe sensor data so as to determine whether the intraoral appliance isbeing worn on a patient's teeth.

The one or more proximity sensors may comprise one or more touch sensors(similarly the touch sensors described herein may be referred to asproximity sensors and/or proximity/touch sensors). The one or more touchsensors can comprise at least one capacitive touch sensor activated bycharges associated with one or more of enamel, gingiva, oral mucosa,saliva, cheeks, lips, or tongue. The one or more touch sensors cancomprise at least one capacitive touch sensor activate by positivecharges associated with plaque or bacteria on the patient's teeth. Theprocessor may optionally be configured to process the sensor data so asto determine an amount of bacteria on the patient's teeth. The one ormore touch sensors can comprise at least one resistive touch sensor.

The one or more touch sensors may comprise at least one capacitive touchsensor configured to use one or more of enamel, gingiva, oral mucosa,saliva, cheeks, lips, or tongue as a ground electrode.

The one or more proximity sensors may comprise one or more of: acapacitive sensor, an eddy-current sensor, a magnetic sensor, an opticalsensor, a photoelectric sensor, an ultrasonic sensor, a Hall Effectsensor, an infrared touch sensor, or a surface acoustic wave (SAW) touchsensor. The one or more proximity sensors may be configured to generatesensing data when in proximity to one or more of the patient's enamel,gingiva, oral mucosa, cheeks, lips, or tongue. The one or more proximitysensors may be integrated with the intraoral appliance, coupled to atooth, or a combination thereof.

The processor may be integrated with the intraoral appliance or coupledto a tooth.

An apparatuses for monitoring usage of an intraoral appliance mayinclude an appliance shell comprising a plurality of teeth receivingcavities and one or more vibration sensors operably coupled to theappliance shell and configured to generate sensor data of intraoralvibration patterns. The device can also comprise a processor operablycoupled to the one or more vibration sensors and configured to processthe sensor data so as to determine whether the intraoral appliance isbeing worn on a patient's teeth. The one or more vibration sensorscomprise one or more of: a MEMS microphone, an accelerometer, or apiezoelectric sensor. The intraoral vibration patterns may be associatedwith one or more of: vibrations transferred to the patient's teeth viathe patient's jaw bone, teeth grinding, speech, mastication, breathing,or snoring. The processor may determine whether the intraoral applianceis being worn by comparing the intraoral vibration patterns topatient-specific intraoral vibration patterns. The one or more vibrationsensors may be integrated with the intraoral appliance, coupled to atooth, or a combination thereof. The processor is integrated with theintraoral appliance or coupled to a tooth.

The various embodiments described herein can be used in combination withvarious types of intraoral appliances worn in a patient's mouth. Theintraoral appliance may be an orthodontic appliance, such as an aligneror wire-and-bracket appliance, used to reposition one or more of thepatient's teeth to a desired arrangement, e.g., to correct amalocclusion. Alternatively or additionally, the intraoral appliance maybe used to maintain one or more of the patient's teeth in a currentarrangement, such as a retainer. Other examples of intraoral appliancessuitable for use in conjunction with the embodiments herein includesleep apnea treatment devices (e.g., mandibular advancement devices orsplints), night guards (e.g., for treating bruxism), mouth guards, andpalatal expanders.

Appliances having teeth receiving cavities that receive and repositionteeth, e.g., via application of force due to appliance resiliency, aregenerally illustrated with regard to FIG. 1A. FIG. 1A illustrates anexemplary tooth repositioning appliance or aligner 100 that can be wornby a patient in order to achieve an incremental repositioning ofindividual teeth 102 in the jaw. The appliance can include a shellhaving teeth-receiving cavities that receive and resiliently repositionthe teeth. An appliance or portion(s) thereof may be indirectlyfabricated using a physical model of teeth. For example, an appliance(e.g., polymeric appliance) can be formed using a physical model ofteeth and a sheet of suitable layers of polymeric material. In someembodiments, a physical appliance is directly fabricated, e.g., usingrapid prototyping fabrication techniques, from a digital model of anappliance.

Although reference is made to an appliance comprising a polymeric shellappliance, the embodiments disclosed herein are well suited for use withmany appliances that receive teeth, for example appliances without oneor more of polymers or shells. The appliance can be fabricated with oneor more of many materials such as metal, glass, reinforced fibers,carbon fiber, composites, reinforced composites, aluminum, biologicalmaterials, and combinations thereof for example. The appliance can beshaped in many ways, such as with thermoforming or direct fabrication(e.g., 3D printing, additive manufacturing), for example. Alternativelyor in combination, the appliance can be fabricated with machining suchas an appliance fabricated from a block of material with computernumeric control machining.

An appliance can fit over all teeth present in an upper or lower jaw, orless than all of the teeth. The appliance can be designed specificallyto accommodate the teeth of the patient (e.g., the topography of thetooth-receiving cavities matches the topography of the patient's teeth),and may be fabricated based on positive or negative models of thepatient's teeth generated by impression, scanning, and the like.Alternatively, the appliance can be a generic appliance configured toreceive the teeth, but not necessarily shaped to match the topography ofthe patient's teeth. In some cases, only certain teeth received by anappliance will be repositioned by the appliance while other teeth canprovide a base or anchor region for holding the appliance in place as itapplies force against the tooth or teeth targeted for repositioning. Insome embodiments, some, most, or even all of the teeth will berepositioned at some point during treatment. Teeth that are moved canalso serve as a base or anchor for holding the appliance as it is wornby the patient. Typically, no wires or other means will be provided forholding an appliance in place over the teeth. In some cases, however, itmay be desirable or necessary to provide individual attachments or otheranchoring elements 104 on teeth 102 with corresponding receptacles orapertures 106 in the appliance 100 so that the appliance can apply aselected force on the tooth. Exemplary appliances, including thoseutilized in the Invisalign® System, are described in numerous patentsand patent applications assigned to Align Technology, Inc. including,for example, in U.S. Pat. Nos. 6,450,807, and 5,975,893, as well as onthe company's website, which is accessible on the World Wide Web (see,e.g., the URL “invisalign.com”). Examples of tooth-mounted attachmentssuitable for use with orthodontic appliances are also described inpatents and patent applications assigned to Align Technology, Inc.,including, for example, U.S. Pat. Nos. 6,309,215 and 6,830,450.

FIGS. 1B-1D illustrate an example of a tooth repositioning system 110including a plurality of appliances 112, 114, 116. Any of the appliancesdescribed herein can be designed and/or provided as part of a set of aplurality of appliances used in a tooth repositioning system. Eachappliance may be configured so a tooth-receiving cavity has a geometrycorresponding to an intermediate or final tooth arrangement intended forthe appliance. The patient's teeth can be progressively repositionedfrom an initial tooth arrangement to a target tooth arrangement byplacing a series of incremental position adjustment appliances over thepatient's teeth. For example, the tooth repositioning system 110 caninclude a first appliance 112 corresponding to an initial tootharrangement, one or more intermediate appliances 114 corresponding toone or more intermediate arrangements, and a final appliance 116corresponding to a target arrangement. A target tooth arrangement can bea planned final tooth arrangement selected for the patient's teeth atthe end of all planned orthodontic treatment. Alternatively, a targetarrangement can be one of some intermediate arrangements for thepatient's teeth during the course of orthodontic treatment, which mayinclude various different treatment scenarios, including, but notlimited to, instances where surgery is recommended, where interproximalreduction (IPR) is appropriate, where a progress check is scheduled,where anchor placement is best, where palatal expansion is desirable,where restorative dentistry is involved (e.g., inlays, onlays, crowns,bridges, implants, veneers, and the like), etc. As such, it isunderstood that a target tooth arrangement can be any planned resultingarrangement for the patient's teeth that follows one or more incrementalrepositioning stages. Likewise, an initial tooth arrangement can be anyinitial arrangement for the patient's teeth that is followed by one ormore incremental repositioning stages.

The various embodiments of the orthodontic appliances presented hereincan be fabricated in a wide variety of ways. As an example, someembodiments of the appliances herein (or portions thereof) can beproduced using indirect fabrication techniques, such as by thermoformingover a positive or negative mold. Indirect fabrication of an orthodonticappliance can involve producing a positive or negative mold of thepatient's dentition in a target arrangement (e.g., by rapid prototyping,milling, etc.) and thermoforming one or more sheets of material over themold in order to generate an appliance shell. Alternatively or incombination, some embodiments of the appliances herein may be directlyfabricated, e.g., using rapid prototyping, stereolithography, 3Dprinting, and the like.

The configuration of the orthodontic appliances herein can be determinedaccording to a treatment plan for a patient, e.g., a treatment planinvolving successive administration of a plurality of appliances forincrementally repositioning teeth. Computer-based treatment planningand/or appliance manufacturing methods can be used in order tofacilitate the design and fabrication of appliances. For instance, oneor more of the appliance components described herein can be digitallydesigned and fabricated with the aid of computer-controlledmanufacturing devices (e.g., computer numerical control (CNC) milling,computer-controlled rapid prototyping such as 3D printing, etc.). Thecomputer-based methods presented herein can improve the accuracy,flexibility, and convenience of appliance fabrication.

In some embodiments, orthodontic appliances, such as the applianceillustrated in FIG. 1A, impart forces to the crown of a tooth and/or anattachment positioned on the tooth at one or more points of contactbetween a tooth receiving cavity of the appliance and received toothand/or attachment. The magnitude of each of these forces and/or theirdistribution on the surface of the tooth can determine the type oforthodontic tooth movement which results. Tooth movements may be in anydirection in any plane of space, and may comprise one or more ofrotation or translation along one or more axes. Types of tooth movementsinclude extrusion, intrusion, rotation, tipping, translation, and rootmovement, and combinations thereof, as discussed further herein. Toothmovement of the crown greater than the movement of the root can bereferred to as tipping. Equivalent movement of the crown and root can bereferred to as translation. Movement of the root greater than the crowncan be referred to as root movement.

FIG. 2 illustrates a method 200 of orthodontic treatment using aplurality of appliances, in accordance with embodiments. The method 200can be practiced using any of the appliances or appliance sets describedherein. In step 210, a first orthodontic appliance is applied to apatient's teeth in order to reposition the teeth from a first tootharrangement to a second tooth arrangement. In step 220, a secondorthodontic appliance is applied to the patient's teeth in order toreposition the teeth from the second tooth arrangement to a third tootharrangement. The method 200 can be repeated as necessary using anysuitable number and combination of sequential appliances in order toincrementally reposition the patient's teeth from an initial arrangementto a target arrangement. The appliances can be generated all at the samestage or time point, in sets or batches (e.g., at the beginning of oneor more stages of the treatment), or one at a time, and the patient canwear each appliance until the pressure of each appliance on the teethcan no longer be felt or until the maximum amount of expressed toothmovement for that given stage has been achieved. A plurality ofdifferent appliances (e.g., a set) can be designed and even fabricatedprior to the patient wearing any appliance of the plurality. Afterwearing an appliance for an appropriate period of time, the patient canreplace the current appliance with the next appliance in the seriesuntil no more appliances remain. The appliances are generally notaffixed to the teeth and the patient may place and replace theappliances at any time during the procedure (e.g., patient-removableappliances). The final appliance or several appliances in the series mayhave a geometry or geometries selected to overcorrect the tootharrangement. For instance, one or more appliances may have a geometrythat would (if fully achieved) move individual teeth beyond the tootharrangement that has been selected as the “final.” Such over-correctionmay be desirable in order to offset potential relapse after therepositioning method has been terminated (e.g., permit movement ofindividual teeth back toward their pre-corrected positions).Over-correction may also be beneficial to speed the rate of correction(e.g., an appliance with a geometry that is positioned beyond a desiredintermediate or final position may shift the individual teeth toward theposition at a greater rate). In such cases, the use of an appliance canbe terminated before the teeth reach the positions defined by theappliance. Furthermore, over-correction may be deliberately applied inorder to compensate for any inaccuracies or limitations of theappliance.

An intraoral appliance can be operably coupled to a monitoring device(also referred to herein as an “electronic compliance indicator”)configured to provide data related to appliance usage and/or patientcompliance, such as data indicative of whether the appliance is beingworn, the amount of time the appliance is worn, and/or interactionbetween the appliance and the intraoral cavity (e.g., contact betweenthe appliance and intraoral tissues, force and/or pressure applied bythe appliance to intraoral tissues). Alternatively or in combination,the monitoring device can be configured to provide data indicative ofone or more characteristics of the patient's intraoral cavity or aportion thereof (e.g., teeth, gingiva, palate, lips, tongue, cheeks,saliva, airway), such as temperature, color, sound, vibration, motion,pH, conductivity, charge, resistance, capacitance, humidity, or gasflow. The characteristics of the patient's intraoral cavity canoptionally be used to determine appliance usage and/or patientcompliance, as discussed in greater detail herein.

The monitoring devices described herein can be designed for use in thepatient's intraoral cavity. For example, the dimensions of a monitoringdevice may be limited in order to avoid patient discomfort and/orfacilitate integration into an intraoral appliance as discussed below.In some embodiments, a monitoring device has a height or thickness lessthan or equal to about 1.5 mm, or less than or equal to about 2 mm. Insome embodiments, a monitoring device has a length or width less than orequal to about 4 mm, or less than or equal to about 5 mm. The shape ofthe monitoring device can be varied as desired, e.g., circular,ellipsoidal, triangular, square, rectangular, etc. For instance, in someembodiments, a monitoring device can have a circular shape with adiameter less than or equal to about 5 mm.

A relatively thin and flexible monitoring device can be used to providea larger surface area while reducing patient discomfort. In someembodiments, the monitoring devices herein are sized to conform to asurface of a tooth crown (e.g., a buccal, lingual, and/or occlusalsurface of a tooth crown). For example, a monitoring device havingdimensions of about 10 mm by about 5 mm can be used to cover a buccalsurface of a molar crown. As another example, a monitoring device havingdimensions of about 10 mm by about 20 mm can be used to cover thebuccal, occlusal, and lingual surfaces of a tooth crown. A monitoringdevice can be in contact with a crown of a single tooth, or with crownsof a plurality of teeth, as desired.

The other properties of the monitoring device (e.g., volume, weight) canbe designed in order to reduce patient discomfort. For instance, theweight of a monitoring device can be selected not to exceed a level thatwould exert undesirable forces on the underlying teeth.

FIG. 3A schematically illustrates a monitoring device 300 (e.g., anECI). The monitoring device 300 can be used in combination with anyembodiment of the systems and devices described herein, and thecomponents of the monitoring device 300 are equally applicable to anyother embodiment of the monitoring devices described herein. Themonitoring device 300 can be implemented as an application-specificintegrated circuit (ASIC) including one or more of the followingcomponents: a processor 302, a memory 304, one or more sensors 306, aclock 308, a communication unit 310, an antenna 312, a power managementunit 314, or a power source 316. The processor 302 (e.g., a centralprocessing unit (CPU), microprocessor, field programmable gate array(FPGA), logic or state machine circuit, etc.), also referred to hereinas a controller, can be configured to perform the various methodsdescribed herein. The memory 304 encompasses various types of memoryknown to those of skill in the art, such as RAM (e.g., SRAM, DRAM), ROM(EPROM, PROM, MROM), or hybrid memory (e.g., flash, NVRAM, EEPROM), andthe like. The memory 304 can be used to store instructions executable bythe processor 302 to perform the methods provided herein. Additionally,the memory can be used to store sensor data obtained by the sensor(s)306, as discussed in greater detail below.

The monitoring device 300 can include any number of sensors 306, such asone, two, three, four, five, or more sensors. In some embodiments, theuse of multiple sensors provides redundancy to increase the accuracy andreliability of the resultant data. Some or all of the sensors 306 can beof the same type. Some or all of the sensors 306 can be of differenttypes. Examples of sensor types suitable for use in the monitoringdevices described herein include: touch or tactile sensors (e.g.,capacitive, resistive), proximity sensors, audio sensors (e.g.,microelectromechanical system (MEMS) microphones), color sensors (e.g.,RGB color sensors), electromagnetic sensors (e.g., magnetic reedsensors, magnetometer), light sensors, force sensors (e.g.,force-dependent resistive materials), pressure sensors, temperaturesensors, motion sensors (e.g., accelerometers, gyroscopes), vibrationsensors, piezoelectric sensors, strain gauges, pH sensors, conductivitysensors, gas flow sensors, gas detection sensors, humidity or moisturesensors, physiological sensors (e.g., electrocardiography sensors,bio-impedance sensors, photoplethysmography sensors, galvanic skinresponse sensors), or combinations thereof. In some embodiments, thesensors herein can be configured as a switch that is activated and/ordeactivated in response to a particular type of signal (e.g., optical,electrical, magnetic, mechanical, etc.).

A sensor 306 can be located at any portion of an intraoral appliance,such as at or near a distal portion, a mesial portion, a buccal portion,a lingual portion, a gingival portion, an occlusal portion, or acombination thereof. A sensor 306 can be positioned near a tissue ofinterest when the appliance is worn in the patient's mouth, such as nearor adjacent the teeth, gingiva, palate, lips, tongue, cheeks, airway, ora combination thereof. For example, when the appliance is worn, thesensor(s) 306 can cover a single tooth, or a portion of a single tooth.Alternatively, the sensor(s) 306 can cover multiple teeth or portionsthereof. In embodiments where multiple sensors 306 are used, some or allof the monitoring devices can be located at different portions of theappliance and/or intraoral cavity. Alternatively, some or all of thesensor 306 can be located at the same portion of the appliance and/orintraoral cavity.

An analog-to-digital converter (ADC) (not shown) can be used to convertanalog sensor data into digital format, if desired. The processor 302can process the sensor data obtained by the sensor(s) 306 in order todetermine appliance usage and/or patient compliance, as describedherein. The sensor data and/or processing results can be stored in thememory 304. Optionally, the stored data can be associated with atimestamp generated by the clock 308 (e.g., a real-time clock orcounter).

The monitoring device 300 may include a communication unit 310configured to transmit the data stored in the memory (e.g., sensor dataand/or processing results) to a remote device. The communication unit310 can utilize any suitable communication method, such as wired orwireless communication methods (e.g., RFID, near-field communication,Bluetooth, ZigBee, infrared, etc.). The communication unit 310 caninclude a transmitter for transmitting data to the remote device and anantenna 312. Optionally, the communication unit 310 includes a receiverfor receiving data from the remote device. In some embodiments, thecommunication channel utilized by the communication unit 310 can also beused to power the device 300, e.g., during data transfer or if thedevice 300 is used passively.

The remote device can be any computing device or system, such as amobile device (e.g., smartphone), personal computer, laptop, tablet,wearable device, etc. Optionally, the remote device can be a part of orconnected to a cloud computing system (“in the cloud”). The remotedevice can be associated with the patient, the treating practitioner,medical practitioners, researchers, etc. In some embodiments, the remotedevice is configured to process and analyze the data from the monitoringdevice 300, e.g., in order to monitor patient compliance and/orappliance usage, for research purposes, and the like.

The monitoring device 300 can be powered by a power source 316, such asa battery. In some embodiments, the power source 316 is a printed and/orflexible battery, such as a zinc-carbon flexible battery, azinc-manganese dioxide printed flexible battery, or a solid-state thinfilm lithium phosphorus oxynitride battery. The use of printed and/orflexible batteries can be advantageous for reducing the overall size ofthe monitoring device 300 and avoiding patient discomfort. For example,printed batteries can be fabricated in a wide variety of shapes and canbe stacked to make three-dimensional structures, e.g., to conform theappliance and/or teeth geometries. Likewise, flexible batteries can beshaped to lie flush with the surfaces of the appliance and/or teeth.Alternatively or in combination, other types of batteries can be used,such as supercapacitors. In some embodiments, the power source 316 canutilize lower power energy harvesting methods (e.g., thermodynamic,electrodynamic, piezoelectric) in order to generate power for themonitoring device 300. Optionally, the power source 316 can berechargeable, for example, using via inductive or wireless methods. Insome embodiments, the patient can recharge the power source 316 when theappliance is not in use. For example, the patient can remove theintraoral appliance when brushing the teeth and place the appliance onan inductive power hub to recharge the power source 316.

Optionally, the monitoring device 300 can include a power managementunit 314 connected to the power source 316. The power management unit314 can be configured to control when the monitoring device 300 isactive (e.g., using power from the power source 316) and when the device300 is inactive (e.g., not using power from the power source 316). Insome embodiments, the monitoring device 300 is only active duringcertain times so as to lower power consumption and reduce the size ofthe power source 316, thus allowing for a smaller monitoring device 300.In some embodiments, the monitoring device 300 includes an activationmechanism (not shown) for controlling when the monitoring device 300 isactive (e.g., powered on, monitoring appliance usage) and when themonitoring device 300 is dormant (e.g., powered off, not monitoringappliance usage). The activation mechanism can be provided as a discretecomponent of the monitoring device 300, or can be implemented by theprocessor 302, the power management unit 314, or a combination thereof.The activation mechanism can be used to reduce the amount of power usedby the monitoring device 300, e.g., by inactivating the device 300 whennot in use, which can be beneficial for reducing the size of the powersupply 316 and thus the overall device size.

In some embodiments, the monitoring device 300 is dormant before beingdelivered to the patient (e.g., during storage, shipment, etc.) and isactivated only when ready for use. This approach can be beneficial inconserving power expenditure. For example, the components of themonitoring device 300 can be electrically coupled to the power source316 at assembly, but may be in a dormant state until activated, e.g., byan external device such as a mobile device, personal computer, laptop,tablet, wearable device, power hub etc. The external device can transmita signal to the monitoring device 300 that causes the activationmechanism to activate the monitoring device 300. As another example, theactivation mechanism can include a switch (e.g., mechanical, electronic,optical, magnetic, etc.), such that the power source 316 is notelectrically coupled to the other components of the monitoring device300 until the switch is triggered. For example, in some embodiments, theswitch is a reed switch or other magnetic sensor that is held open by amagnet. The magnet can be removably attached to the monitoring device300, or may be integrated into the packaging for the device 300 orappliance, for example. When the monitoring device is separated from themagnet (e.g., by removing the magnet or removing the device andappliance from the packaging), the switch closes and connects the powersource 316. As another example, the monitoring device 300 can include amechanical switch such as a push button that is manually actuated inorder to connect the power source 316. In some embodiments, theactivation mechanism includes a latching function that locks the switchupon the first actuation to maintain connectivity with the power sourceso as to maintain activation of the monitoring device 300. Optionally,the switch for the activation mechanism can be activated by a componentin the patient's intraoral cavity (e.g., a magnet coupled to a patient'stooth), such that the monitoring device 300 is active only when theappliance is worn by the patient, and is inactive when the appliance isremoved from the patient's mouth. Alternatively or in combination, theswitch can be activated by other types of signals, such as an opticalsignal.

FIG. 23 illustrates a monitoring device 2300 with an activationmechanism, in accordance with embodiments. The monitoring device 2300,as with all other monitoring devices described herein, can be similar tothe monitoring device 300, and can include some or all of the componentsdescribed herein with respect to the monitoring device 300. The device2300 is coupled to an intraoral appliance 2302 (e.g., via anencapsulating material 2304). The device 2300 can include an activationmechanism 2303 including a magnetic switch. Prior to use, the device2300 can be removably coupled to a magnet 2306 (e.g., using tape 2308),and the magnet 2306 can hold the magnetic switch in an open positionsuch that the device 2300 is inactive. When the appliance 2302 is readyfor use, the user can remove the magnet 2306, thus closing the magneticswitch and connecting the components of the monitoring device 2300 to apower source. The intraoral appliances and monitoring devices describedherein can be configured in many different ways. In some embodiments, anintraoral appliance as described herein is operably coupled to a singlemonitoring device. Alternatively, the intraoral appliance can beoperably coupled to a plurality of monitoring devices, such as at leasttwo, three, four, five, or more monitoring devices. Some or all of themonitoring devices may be of the same type (e.g., collect the same typeof data). Alternatively, some or all of the monitoring devices may be ofdifferent types (e.g., collect different types of data). Any of theembodiments of monitoring devices described herein can be used incombination with other embodiments in a single intraoral appliance.

A monitoring device can be located at any portion of the appliance, suchas at or near a distal portion, a mesial portion, a buccal portion, alingual portion, a gingival portion, an occlusal portion, or acombination thereof. The monitoring device can be positioned near atissue of interest when the appliance is worn in the patient's mouth,such as near or adjacent the teeth, gingiva, palate, lips, tongue,cheeks, airway, or a combination thereof. For example, when theappliance is worn, the monitoring device can cover a single tooth, or aportion of a single tooth. Alternatively, the monitoring device cancover multiple teeth or portions thereof. In embodiments where multiplemonitoring devices are used, some or all of the monitoring devices canbe located at different portions of the appliance. Alternatively, someor all of the monitoring devices can be located at the same portion ofthe appliance.

A monitoring device can be operably coupled to the intraoral appliancein a variety of ways. For example, the monitoring device can bephysically integrated with the intraoral appliance by coupling themonitoring device to a portion of the appliance (e.g., using adhesives,fasteners, latching, laminating, molding, etc.). The coupling may be areleasable coupling allowing for removal of the monitoring device fromthe appliance, or may be a permanent coupling in which the monitoringdevice is permanently affixed to the appliance. Alternatively or incombination, the monitoring device can be physically integrated with theintraoral appliance by encapsulating, embedding, printing, or otherwiseforming the monitoring device with the appliance. In some embodiments,the appliance includes a shell shaped to receive the patient's teeth,and the monitoring device is physically integrated with the shell. Themonitoring device can be located on an inner surface of the shell (e.g.,the surface adjacent to the received teeth), an outer surface of theshell (e.g., the surface away from the received teeth), or within a wallof the shell. Optionally, as discussed further herein, the shell caninclude a receptacle shaped to receive the monitoring device. Exemplarymethods for fabricating an appliance with a physically integratedmonitoring device (e.g., by incorporating some or all of the componentsof the monitoring device during direct fabrication of the appliance) aredescribed in further detail herein.

In general any of the apparatuses described herein may be used inconjunction with digital model(s) or scans or the patient's teeth and/orintraoral appliance. For example, FIG. 3B schematically illustrates asystem 383 including an intraoral appliance 377 with one or moresensors, and digital scan data of the appliance and/or patient's teeth379. An analysis engine 381 (which may be part of the intraoralappliance or separate from the intraoral appliance) may integrate thedistal information and the sensor information, and may relate thespecific sensor information to the patient's teeth using the digitalscan data.

FIGS. 4A and 4B illustrate an intraoral appliance 400 including anintegrated monitoring device 402, in accordance with embodiments. Theappliance 400 includes a shell 404 having a plurality of teeth receivingcavities, and the monitoring device 402 is coupled to an outer, buccalsurface of the shell 404 adjacent a tooth receiving cavity 406. In thedepicted embodiment, the monitoring device 402 is coupled to a toothreceiving cavity 406 for a molar. It shall be appreciated that inalternative embodiments, the monitoring device 402 can be coupled toother portions of the shell 404, such as an inner surface, a lingualsurface, an occlusal surface, one or more tooth receiving cavities forother types of teeth (e.g., incisor, canine, premolar), etc. Themonitoring device 402 can be shaped to conform to the geometry of thecorresponding appliance portion (e.g., the wall of the cavity 306) so asto provide a lower surface profile and reduce patient discomfort. Insome embodiments, the appliance 400 includes a receptacle 408 formed onthe outer surface of the shell 404 and the monitoring device 402 ispositioned within the receptacle. Exemplary methods for forming anappliance with a receptacle 408 and integrated monitoring device 402 aredescribed in detail below.

The monitoring device 402 can include any of the components previouslydescribed herein with respect to the monitoring device 300 of FIG. 3A.For example, the monitoring device 402 can include a sensor 410, a powersource 412 (e.g., a battery), and/or a communication unit 414 (e.g., awireless antenna). The arrangement of the components of the monitoringdevice 402 can be varied as desired. In some embodiments, the sensor 408is located adjacent to the tooth receiving cavity 406. A gap can beformed in the shell 404 adjacent to the sensor 410 so as to permitdirect access to the received tooth. The communication unit 414 (or acomponent thereof, such as an antenna) can be located adjacent to or onthe outer surface of the receptacle 408 so as to facilitate datatransmission.

In some embodiments, some of the components of a monitoring device maybe packaged and provided separately from other components of the device.For example, a monitoring device can include one or more components thatare physically integrated with a first intraoral appliance and one ormore components that are physically integrated with a second intraoralappliance. The first and second intraoral appliances can be worn onopposing jaws, for example. Any of the components of a monitoring device(e.g., components of the device 300 of FIG. 3A) can be located on anappliance for the upper jaw, an appliance for the lower jaw, or acombination thereof. In some embodiments, it is beneficial to distributethe components of the monitoring device across multiple appliances inorder to accommodate space limitations, accommodate power limitations,and/or improve sensing, for example. Additionally, some of thecomponents of a monitoring device can serve as a substrate for othercomponents (e.g., a battery serves as a substrate to an antenna). FIG. 5illustrates a monitoring system 500 including a first appliance 502 anda second appliance 504, in accordance with embodiments. The firstappliance 502 can be shaped to receive teeth of a patient's upper archand the second appliance 504 can be shaped to receive teeth of apatient's lower arch. The system 500 can include a monitoring deviceseparated into a first subunit 506 physically integrated with the firstappliance 502 and a second subunit 508 physically integrated with thesecond appliance 508. In some embodiments, the first subunit 506 is apower supply subunit including a power source 510, and the secondsubunit 508 is a sensing subunit including the remaining components ofthe monitoring device, such as a power management unit 512, processor(e.g., CPU 514), sensor 516, memory (e.g., RAM 518 such as SRAM or DRAM;ROM such as EPROM, PROM, or MROM; or hybrid memory such as EEPROM 520,flash, or NVRAM), communication unit (e.g., antenna 522), or any othercomponent 524 described herein (e.g., with respect to the monitoringdevice 300 of FIG. 3A). The first subunit 506 and second subunit 508 canbe operably coupled to each other via inductive coupling between thepower supply 510 and power management unit 512, e.g., when the firstappliance 502 and second appliance 504 are brought into proximity witheach other by the closing of the patient's jaws.

The configuration of FIG. 5 can be varied as desired. For example, thefirst subunit 506 can be physically integrated with the second appliance504 and the second subunit 508 can be physically integrated with thefirst appliance 502. As another example, the distribution of themonitoring device components between the first subunit 506 and secondsubunit 508 can differ from the depicted embodiment.

Alternatively or in combination, a monitoring device can include one ormore components that are physically integrated with an intraoralappliance and one or more components that are physically integrated withanother device external to the patient's intraoral cavity. For example,the external device can be a wearable device (e.g., headgear, smartwatch, wearable computer, etc.) worn on another portion of the patient'sbody. As another example, the external device can be a power hub, amobile device, personal computer, laptop, tablet, etc. Any of thecomponents of a monitoring device (e.g., components of the device 300 ofFIG. 3A) can be located on an external device. In some embodiments, themonitoring device includes a communication unit and antenna integratedinto the intraoral appliance that transmits sensor data from thepatient's intraoral cavity to the external device, and optionallyreceives data from the external device. The monitoring device componentsintegrated into the external device can provide additional functionality(e.g., processing and/or analysis capabilities) that augments thefunctionality of the monitoring device components within the intraoralappliance. The monitoring device components within the intraoralappliance may be capable of operating with or without the augmentedfunctionalities.

Alternatively or in combination, a monitoring device can include one ormore components that are physically integrated with an intraoralappliance and one or more components that are located in the patient'sintraoral cavity separate from the appliance. The intraoral componentscan be positioned so as to interact with (e.g., physically contact,communicate with) the integrated components in the appliance when theappliance is worn. In some embodiments, the intraoral components arecoupled to a portion of the intraoral cavity, such as a crown of thepatient's tooth. For instance, the intraoral components can bephysically integrated into an attachment device mounted on a patient'stooth. Alternatively or in combination, the monitoring device can besurgically implanted, e.g., in the bone of the patient's jaw. Any of thecomponents of a monitoring device (e.g., components of the device 300 ofFIG. 3A) can be located in the patient's intraoral cavity rather than inthe intraoral appliance. In some embodiments, the appliance andintegrated components can be removed from the patient's mouthindependently of the intraoral components. Advantageously, this approachmay reduce costs by allowing the same device components to be used withmultiple different appliances, e.g., when applying a sequence of shellappliances to reposition the patient's teeth.

FIG. 6A illustrates a system 600 including an intraoral appliance 602and an attachment device 604 mounted on a tooth 606, in accordance withembodiments. The appliance 602 can include a shell with a toothreceiving cavity shaped to receive the tooth 606 and a receptacle shapedto accommodate the attachment device 604 on the tooth 606. In someembodiments, the system 600 includes a monitoring device having a firstsubunit physically integrated into the appliance 602 (e.g., according toany of the methods described herein) and a second subunit physicallyintegrated into the attachment device 604. In some embodiments, thesecond subunit integrated into the attachment device 604 includes therelatively bulky components of the monitoring device, such as the powersource, memory, and/or sensors. For example, the attachment device 604can include a battery or other power source operably coupled to themonitoring device components integrated into the appliance 602, e.g.,via inductive coupling or direct contact using electrodes 608. Inalternative embodiments, this configuration can be reversed, with thepower source mounted in the appliance 602 and the remaining monitoringdevice components located in the attachment device 604. This approachcan reduce costs when multiple appliances are used, since only the powersource is replaced with each new appliance. As another example, theattachment device 604 can include a passive sensing element driven byone or more monitoring device components located in the appliance 602.In yet another example, the attachment device 604 can include aconductive element used to trigger a switch integrated in the appliance602.

FIG. 6B illustrates a system 650 including an intraoral appliance 652and an attachment device 654 mounted on a tooth 656, in accordance withembodiments. Similar to the appliance 600, the appliance 652 can includea shell with a tooth receiving cavity shaped to receive the tooth 656and a receptacle shaped to accommodate the attachment device 654 on thetooth 656. In some embodiments, the system 650 includes a monitoringdevice having a first subunit physically integrated into the appliance652 (e.g., according to any of the methods described herein) and asecond subunit physically integrated into the attachment device 654. Thefirst subunit in the appliance 652 can include a sensing target 658 andthe second subunit in the attachment device 654 can include one or moresensors configured to detect the target. For example, the sensing target658 can be a mirror or opaque surface and the sensor can be aphotodetector. As another example, the sensing target 658 can be amagnet and the sensor can be a magnetometer. In yet another example, thesensing target 658 can be a metallic element (e.g., foil, coating) andthe sensor can be a capacitive sensor. Optionally, the sensing target658 can be a powered coil generating an AC electromagnetic field, suchthat the sensor also obtains power from the sensing target 658. Inalternative embodiments, the locations of the first and second subunitscan be reversed, such that the sensing target 658 is located in theattachment device 654 and the sensor is located in the appliance 652.

The monitoring devices of the present disclosure may utilize manydifferent types and configurations of sensors. The description below ofcertain exemplary monitoring devices is not intended to be limiting, andit shall be appreciated that the features of the various embodimentsdescribed herein can be used in combination with features of otherembodiments. For example, the monitoring devices discussed below mayalso include any of the components previously described with respect tothe monitoring device 300 of FIG. 3A. A single monitoring device caninclude any combination of the sensor types and sensor configurationsdescribed herein.

In some embodiments, a monitoring device includes a structure shaped tointeract with the sensor when the intraoral appliance is worn on thepatient's teeth. The monitoring device can include one or moredeflectable structures (e.g., a cantilever, dimple, concavity, flap,protrusion, pop-out structure, etc.) formed with or coupled to theappliance. The deflectable structure can be deflected outward by thepatient's tooth or an attachment device coupled to the tooth when theappliance is worn, for example. In some embodiments, the monitoringdevice includes a sensor (e.g., a mechanical switch such as a pushbutton), an electrical switch, an optical switch, a proximity sensor, atouch sensor, etc., configured to generate sensor data indicative ofdeflection of the deflectable structure (e.g., whether the structure isdeflected, the deflection distance, etc.). The monitoring device canalso include a processor operably coupled to the sensor and configuredto process the sensor data so as to generate appliance usage and/orcompliance data (e.g., information regarding whether the appliance isbeing worn). Optionally, the sensor can provide more complex data (e.g.,force and/or pressure data) regarding the interaction between theappliance and the patient's teeth. In some embodiments, the deflectablestructure is in a deflected state when the appliance is being worn andin a resting state when the appliance is not being worn, and thedeflectable structure interacts with (e.g., activates) the sensor onlywhen in the deflected state.

FIGS. 7A and 7B illustrate a monitoring device 700 with a deflectablestructure 702, in accordance with embodiments. In the depictedembodiment, the deflectable structure 702 is formed in a shell 704 of anintraoral appliance, e.g., in a wall of a tooth receiving cavity 706.The monitoring device 700 can include a sensor 708 (e.g., push button)configured to detect the deflection of the deflectable structure 702.When the appliance is not being worn on the patient's teeth (FIG. 7A),the deflectable structure 702 can be in a resting state such that thesensor 708 is not activated. When the appliance is worn by the patient,the tooth 710 (e.g., a first or second molar) can displace thedeflectable structure 702 outwards to activate the sensor 708. Thedeflection distance can be varied as desired. For instance, thestructure 702 can be deflected outward by a distance of at least about25 μm, at least about 30 μm, at least about 50 μm, at least about 100μm, at least about 200 (μm, at least about 300 μm, or a distance withina range from about 25 μm to about 300 μm. The monitoring device 700 caninclude other components (e.g., as previously described with respect toFIG. 3A) for storing, processing, analyzing, and/or transmitting thesensor data.

FIG. 7C illustrates a monitoring device 720 with a deflectable structure722, in accordance with embodiments. The deflectable structure 722 isformed in a shell of an intraoral appliance, e.g., in a wall of a toothreceiving cavity 724. The tooth receiving cavity 724 is shaped toreceive a tooth 726 coupled to an attachment device 728. In someembodiments, the attachment device 728 includes an activator structure730 that deflects the deflectable structure 722 when the tooth 726 isreceived in the cavity 724. The monitoring device 720 includes a sensingsubunit 732 mounted to the shell near the deflectable structure 722. Thesensing subunit 732 includes a sensor 734 (e.g., a switch) that isactivated by the deflection of the deflectable structure 722.Optionally, the sensor 732 can be covered with a flexible membrane. Thesubunit 732 can also include a power source, a processor, and/or any ofthe other monitoring device components described herein (e.g., withrespect to the embodiment of FIG. 3A).

FIG. 7D illustrates a method for fabricating an intraoral appliance witha deflectable structure, in accordance with embodiments. In the firststep, a mold 750 of a patient's dentition is provided. The mold 750 canrepresent the patient's teeth in a current or target tooth arrangement,for example. In a second step, an intraoral appliance 752 is formed byforming (e.g., thermoforming) a material over the mold 750.Alternatively, the intraoral appliance 752 can be formed by directfabrication (e.g., stereolithography, 3D printing, etc.) without usingthe mold 750. The appliance can include a shell with a tooth receivingcavity 754 having a dimple or concavity 756 at the target location forthe deflectable structure. In a third step, a deflectable structure 758is formed in the appliance 752 by cutting the wall of the cavity 754 soas to form a cantilevered portion. Cutting of the appliance 752 can beperformed using methods known to those of skill in the art, such aslaser cutting or milling. Subsequently, the other components of themonitoring device can be coupled to the appliance 752 adjacent to ornear the deflectable structure 758.

Alternatively or in combination, a monitoring device can include one ormore proximity sensors configured to generate sensor data when inproximity to a sensing target. Examples of proximity sensors suitablefor use with the embodiments herein include capacitive sensors,resistive sensors, inductive sensors, eddy-current sensors, magneticsensors, optical sensors, photoelectric sensors, ultrasonic sensors,Hall Effect sensors, infrared touch sensors, or surface acoustic wave(SAW) touch sensors. A proximity sensor can be activated when within acertain distance of the sensing target. The distance can be about lessthan 1 mm, or within a range from about 1 mm to about 50 mm. In someembodiments, a proximity sensor can be activated without direct contactbetween the sensor and the sensing target (e.g., the maximum sensingdistance is greater than zero).

In some embodiments, a proximity sensor is activated when in directcontact with the sensing target (the sensing distance is zero), alsoknown as a touch or tactile sensor. Examples of touch sensors includecapacitive touch sensors, resistive touch sensors, inductive sensors,pressure sensors, and force sensors. In some embodiments, a touch sensoris activated only by direct contact between the sensor and the sensingtarget (e.g., the maximum sensing distance is zero). Some of theproximity sensor types described herein (e.g., capacitive sensors) mayalso be touch sensors, such that they are activated both by proximity tothe sensing target as well as direct contact with the target.

One or more proximity sensors may be integrated in the intraoralappliance and used to detect whether the appliance is in proximity toone or more sensing targets. The sensing targets can be an intraoraltissue (e.g., the teeth, gingiva, palate, lips, tongue, cheeks, or acombination thereof). For example, proximity sensors can be positionedon the buccal and/or lingual surfaces of an appliance in order to detectappliance usage based on proximity to and/or direct contact with thepatient's cheeks and/or tongue. As another example, one or moreproximity sensors can be positioned in the appliance so as to detectappliance usage based on proximity to and/or direct contact with theenamel and/or gingiva. In some embodiments, multiple proximity sensorsare positioned at different locations appliance so as to detectproximity to and/or direct contact with different portions of theintraoral cavity.

Alternatively or in combination, one or more sensing targets can becoupled to an intraoral tissue (e.g., integrated in an attachment deviceon a tooth), or can be some other component located in the intraoralcavity (e.g., a metallic filling). Alternatively or in combination, oneor more proximity sensors can be located in the intraoral cavity (e.g.,integrated in an attachment device on a tooth) and the correspondingsensing target(s) can be integrated in the intraoral appliance.Optionally, a proximity sensor integrated in a first appliance on apatient's upper or lower jaw can be used to detect a sensing targetintegrated in a second appliance on the opposing jaw or coupled to aportion of the opposing jaw (e.g., attached to a tooth), and thus detectproximity and/or direct contact between the patient's jaws.

The proximity sensor may be a capacitive sensor activated by charges onthe sensing target. The capacitive sensor can be activated by chargesassociated with intraoral tissues or components such as the enamel,gingiva, oral mucosa, saliva, cheeks, lips, and/or tongue. For example,the capacitive sensor can be activated by charges (e.g., positivecharges) associated with plaque and/or bacteria on the patient's teethor other intraoral tissues. In such embodiments, the capacitive sensingdata can be used to determine whether the appliance is being worn, andoptionally the amount of plaque and/or bacteria on the teeth. As anotherexample, the capacitive sensor can be activated by charges associatedwith the crowns of teeth, e.g., negative charges due to the presence ofionized carboxyl groups covalently bonded to sialic acid.

Various configurations of capacitive sensors can be used for themonitoring devices described herein. In some embodiments, the electricalcharges on the surface of an intraoral tissue can interfere with theelectric field of the capacitive sensor. Alternatively or incombination, the intraoral tissue can serve as the ground electrode ofthe capacitive sensor. Optionally, a shielding mechanism can be used toguide the electric field of the capacitive sensor in a certain locationand/or direction for detecting contact with a particular tissue.

FIG. 8A illustrates an intraoral appliance 800 including a capacitivesensor 802, in accordance with embodiments. In some embodiments, thesensing target for the capacitive sensor 802 is the surface of thepatient's tooth 804, and the capacitive sensor 802 is coupled to theinner surface of a tooth receiving cavity 806 of an intraoral applianceso as to be adjacent to the tooth 804 when the appliance is worn. Thecapacitive sensor 802 can be activated by proximity to the tooth 804and/or direct contact with the tooth 804. In some embodiments, thecapacitive sensor 802 is activated by negative charges on the enamel ofthe tooth crown. Alternatively or in combination, the capacitive sensor802 can be activated by positive charges associated with plaque and/orbacteria on the tooth crown. Optionally, the capacitive sensor 802 canbe activated by charges associated with minerals in the patient's salivaon the tooth surface, including but not limited to NH4+, Ca2+, PO43″,HCO3−, and F.

FIG. 8B illustrates a monitoring device 850 integrated into an intraoralappliance 852, in accordance with embodiments. The monitoring device 850can be located on any suitable portion of the appliance 852, such as abuccal surface and/or lingual surface of the appliance 852 adjacent atooth receiving cavity. The device 850 can include a capacitive sensor854 (e.g., a capacitive touch sensor grid). The capacitive sensor 854can be similar to the sensor 802 described with respect to FIG. 8A, forexample. In some embodiments, the capacitive sensor 854 is flexibleand/or thermoformable so as to conform to the shape of the appliance852. The monitoring device 850 can also include a controller and powersource 856 coupled to the capacitive sensor 854, as well as any of theother components described herein with respect to the monitoring device300 of FIG. 3A. The controller and power source 856 can be used to powerthe capacitive sensor 854, process proximity and/or contact dataobtained by the capacitive sensor 854, store the obtained data and/orprocessing results, and/or transmit the data and/or processing resultsto a remote device, for example.

Although FIG. 8B illustrates a single monitoring device 850 with asingle capacitive sensor 854, other configurations can also be used. Forexample, in alternative embodiments, the monitoring device 850 caninclude multiple capacitive sensors located at different sites on theappliance 852 to detect proximity to and/or contact with multiplelocations in the intraoral cavity. Optionally, multiple monitoringdevices can be used, with each device being coupled to one or morerespective capacitive sensors.

In some variations, the majority of (or all of) the intraoral appliance(shown in this example as an aligner, but as mentioned above, may beconfigured as any other intraoral appliance) may include a capacitivetouch-sensor material. In FIG. 8C, the aligner 890 includes a formedsurface of capacitive touch-sensor material 893. FIG. 8D shows anenlarged view, showing a grid pattern of the capacitive touch sensorthat may be distributed across the surface of the intraoral appliance ofFIG. 8C.

The capacitive touch sensor may relate intensity and location of touchinformation, and may derive force (force moment, and force direction) onthe patient's teeth from the intraoral appliance. In some variations theappliance may include one or more processors for receiving touchinformation from the grid of capacitive sensors and may correlate thisinformation with applied force on the teeth by the apparatus. Forexample, the capacitive touch data may be correlate to particular teethusing a digital model of the patient's teeth and/or aligner (asdiscussed above generally in FIG. 3B).

FIG. 9 illustrates a monitoring system 900 for detecting proximitybetween the patient's jaws, in accordance with embodiments. The system900 includes a first appliance 902 worn on the patient's upper teeth anda second appliance 904 worn on the patient's lower teeth. The system 900also includes a monitoring device including a first sensing subunit 906(e.g., a first plate) integrated with the first appliance 902, a secondsensing subunit 908 (e.g., a second plate) integrated with the secondappliance 904, and a controller 910 integrated with the first appliance902 and coupled to the first sensing subunit 906. Alternatively, thecontroller 910 can be integrated with the second appliance 904 andcoupled to the second sensing subunit 908. In some embodiments, themonitoring device is used to measure the capacitance and/or chargebetween first sensing subunit 906 and the second sensing subunit 908,and the measurement data can be used to determine whether the patient'sjaws are in proximity to each other.

Alternatively or in combination, a monitoring device can include one ormore vibration sensors configured to generate sensor data indicative ofintraoral vibration patterns. Examples of vibration sensors includeaudio sensors (e.g., MEMS microphones), accelerometers, andpiezoelectric sensors. The intraoral vibration patterns can beassociated with one or more of: vibrations transferred to the patient'steeth via the patient's jaw bone, teeth grinding, speech, mastication,breathing, or snoring. In some embodiments, the intraoral vibrationpatterns originate from sounds received by the patient's ear drums. Theintraoral vibration patterns may also originate from intraoralactivities, such as teeth grinding, speech, mastication, breathing,snoring, etc. The sensor data generated by the vibration sensors can beprocessed to determine appliance usage and/or patient compliance. Forinstance, the monitoring device can include a processor that comparesthe detected intraoral vibration patterns to patient-specific intraoralvibration patterns to determine whether the appliance is being worn on apatient's teeth. In some embodiments, the processor is trained usingprevious data of patient-specific intraoral vibration patterns, and thendetermines whether the appliance is being worn by matching the measuredpatterns to the previous patterns. Alternatively or in combination,appliance usage can be determined by comparing the measured vibrationpatterns to vibration patterns obtained when the appliance is not beingworn.

Alternatively or in combination, a monitoring device can include one ormore optical sensors configured to detect appliance usage based onoptical signals. For example, the optical sensors can be color sensors(e.g., mono-channel color sensors, multi-channel color sensors such asRGB sensors) configured to detect the colors of intraoral tissues. Insome embodiments, one or more color sensors can be integrated into theintraoral appliance so as to be positioned adjacent to certain intraoraltissue (e.g., enamel, gingiva, cheeks, tongue, etc.) when the applianceis worn in the mouth. The device can determine whether the appliance iscurrently being worn based on whether the colors detected by the sensorsmatch the expected colors for the tissues. In such embodiments, themonitoring device can include one or more light sources (e.g., LEDs)providing illumination for the color sensors.

As another example, the monitoring device can include one or moreemitters (e.g., a LED) configured to generate optical signals and one ormore optical sensors (e.g., a photodetector) configured to measure theoptical signals. For example, an emitter can be positioned such thatwhen the appliance is worn, the optical signal is reflected off of asurface (e.g., an intraoral tissue, a portion of an intraoral appliance)in order to reach the corresponding optical sensor. In some embodiments,when the appliance is not being worn, the optical signal is notreflected and does not reach the optical sensor. Accordingly, activationof the optical sensor can indicate that the appliance is currently beingworn.

FIG. 10A illustrates a monitoring device 1000 utilizing optical sensing,in accordance with embodiments. The device 1000 includes an emitter 1002and an optical sensor 1004 integrated into an intraoral appliance 1006.In the depicted embodiment, the emitter 1002 and sensor 1004 are bothlocated on a buccal surface of the appliance 1006 such that opticalsignals from the emitter 1002 are reflected off the patient's cheek 1008to reach the sensor 1004 when the appliance 1006 is worn. In alternativeembodiments, the emitter 1002 and sensor 1004 can be located on alingual surface of the appliance 1006 such that optical signals fromemitter 1002 are reflected off the patient's tongue to reach the sensor1004.

FIG. 10B illustrates a monitoring device 1020 using optical sensing, inaccordance with embodiments. The device 1020 includes an emitter 1022and an optical sensor 1024 integrated into a first intraoral appliance1026 worn on a jaw of the patient (e.g., upper or lower jaw). Theemitter 1022 and sensor 1024 can be arranged such that optical signalsfrom the emitter 1022 reflect off of a second intraoral appliance 1028worn on the patient's opposing jaw to reach the sensor 1024 when thefirst appliance 1026 and second appliance 1028 are being worn.Optionally, the second appliance 1028 can include a surface 1030 withoptical properties selected to enhance and/or control reflection of theoptical signal.

As another example, the emitter can be positioned such that when theappliance is worn, the optical signal is transmitted directly to theoptical sensor without requiring any reflection off another surface. Insome embodiments, when the appliance is not being worn, the opticalsignal does not reach the optical sensor. Accordingly, activation of theoptical sensor can indicate that the appliance is currently being worn.

FIG. 10C illustrates a monitoring device 1040 using optical sensing, inaccordance with embodiments. The device 1040 includes an emitter 1042integrated into a first intraoral appliance 1044 worn on a jaw of thepatient (e.g., upper or lower jaw) and an optical sensor 1046 integratedinto a second intraoral appliance 1048 worn on the patient's opposingjaw. The emitter 1042 and sensor 1046 can be arranged such that theoptical signals from the emitter 1042 are transmitted directly to thesensor 1046 when the first appliance 1044 and second appliances 1048 areworn. In yet another example, the emitter can be positioned such thatwhen the appliance is worn, the optical signal is occluded by anintraoral tissue (e.g., the patient's tongue). In some embodiments, whenthe appliance is not being worn, the optical signal is not occluded andreaches the optical sensor (e.g., via direct transmission or reflectionfrom a surface). Accordingly, activation of the optical sensor canindicate that the appliance is not currently being worn. Optionally, theoptical signal can be infrared light in order to be less obtrusive tothe patient.

FIGS. 11A and 11B illustrate a monitoring device 1100 using opticalsensing, in accordance with embodiments. The device 1100 includes anemitter 1102 and optical sensor 1104 integrated into an intraoralappliance 1106. The emitter 1102 and sensor 1104 can be positioned onopposing sides of the lingual surface of the appliance 1106 such thatoptical signals are transmitted directly from the emitter 1102 to thesensor 1104 when the appliance 1106 is not being worn (FIG. 11A). Whenthe appliance 1106 is worn (FIG. 11B), the patient's tongue 1108 canocclude the transmission of optical signals between the emitter 1102 andsensor 1104.

FIGS. 11C and 11D illustrate a monitoring device 1120 using opticalsensing, in accordance with embodiments. The device 1120 includes anemitter 1122 and optical sensor 1124 integrated into an intraoralappliance 1126. The emitter 1122 and sensor 1124 can be positioned thesame side of the lingual surface of the appliance 1126 such that opticalsignals generated by the emitter 1122 are reflected off the opposinglingual surface 1128 to the sensor 1124 when the appliance 1126 is notbeing worn (FIG. 11C). Optionally, the optical properties of the surface1128 can be selected to enhance and/or control the reflection of theoptical signal. When the appliance 1126 is worn (FIG. 11D), thepatient's tongue 1130 can occlude the transmission of optical signalsbetween the emitter 1122 and sensor 1124.

Additionally, the optical sensing-based monitoring devices describedherein can also be configured to detect variations in the reflectedand/or transmitted optical signal caused by breathing, mastication, orother patient movements. This information can be used to further improvethe reliability and accuracy of optical-sensing based compliancemonitoring.

Alternatively or in combination, the monitoring devices of the presentdisclosure can include one or more magnetic sensors configured to detectappliance usage based on changes to a magnetic field. Examples ofmagnetic sensors suitable for use with the embodiments herein includemagnetometers, Hall Effect sensors, magnetic reed switches, andmagnetoresistive sensors. In some embodiments, the characteristics ofthe magnetic field (e.g., magnitude, direction) vary based on whetherthe appliance is currently being worn, e.g., due to interference fromintraoral tissues such as the teeth. Accordingly, the device candetermine appliance usage by processing and analyzing the magnetic fielddetected by the magnetic sensors.

FIGS. 12A and 12B illustrate a monitoring device 1200 using magneticsensing, in accordance with embodiments. The device 1200 includes amagnet 1202 and a sensing subunit 1204 coupled to an intraoral appliance1206. For example, the appliance 1206 can include a shell withtooth-receiving cavities and the magnet 1202 and sensing subunit 1204can be coupled to the outer surface of a tooth receiving cavity. Thesensing subunit 1204 includes one or more magnetic sensors 1208 (e.g.,three magnetometers) configured to measure the characteristics (e.g.,magnetic, direction) of the magnetic field generated by the magnet 1202.In some embodiments, when the appliance 1206 is worn by the patient, thetooth 1210 received in the cavity interferes with the magnetic field(FIG. 12B), such that the field characteristics differ from when theappliance is not being worn (FIG. 12A). The monitoring device 1200 caninclude a processor (not shown) configured to determine whether theappliance is being worn based on the sensing data produced by themagnetic sensor(s) 1208.

FIG. 12C illustrates a monitoring device 1220 using magnetic sensing, inaccordance with embodiments. The device 1220 includes a magnetic sensor1222 (e.g., a Hall Effect sensor or a magnetoresistive sensor)integrated into a first intraoral appliance 1224 worn on a patient's jaw(e.g., upper or lower jaw). The magnetic sensor 1222 is used to detect amagnetic field generated by a magnet 1226 integrated into a secondintraoral appliance 1228 worn on the opposing jaw. In some embodiments,the characteristics of the magnetic field vary based on whether thefirst appliance 1224 and second appliance 1228 are being worn on thepatient's teeth. The monitoring device 1220 can include a processor (notshown) configured to determine whether the appliances are being wornbased on the sensing data produced by the magnetic sensors 1222.

A magnetic sensing-based monitoring device may include a ferromagnetictarget (e.g., a metal plate) that alters the characteristics of themagnetic field when the appliance is worn. The ferromagnetic target canbe integrated into an intraoral appliance or an attachment devicemounted on a tooth, or can be an existing element in the intraoralcavity (e.g., a metal filling, implant, etc.). The monitoring device candetect whether the patient is using the appliance by sensing thecharacteristics of the magnetic field and detecting whether theferromagnetic target is present.

FIG. 13A illustrates a monitoring device 1300 using magnetic sensing, inaccordance with embodiments. The monitoring device 1300 includes asensing subunit 1302 integrated into a first intraoral appliance 1304worn on a patient's jaw (e.g., upper or lower jaw) and a ferromagnetictarget 1306 (e.g., a metal plate) integrated into a second intraoralappliance 1308 worn on the opposing jaw. The sensing subunit 1302 caninclude a magnet 1310 and a magnetic sensor 1312 that detect themagnetic field generated by the magnet 1310. In some embodiments, whenthe first appliance 1304 and second appliance 1308 are worn by thepatient, the presence of the ferromagnetic target 1306 alters thecharacteristics of the generated magnetic field. The monitoring device1300 can include a processor (not shown) configured to determine whetherthe appliances are being worn based on the sensing data produced by themagnetic sensor 1312.

FIG. 13B illustrates a monitoring device 1320 using magnetic sensing, inaccordance with embodiments. The monitoring device 1320 includes asensing subunit 1322 integrated into an attachment device coupled to atooth 1324 in a patient's jaw (e.g., upper or lower jaw) and aferromagnetic target 1326 (e.g., a metal plate) integrated into anintraoral appliance 1328 worn on the opposing jaw. Optionally, a secondintraoral appliance 1329 including a cavity shaped to receive the tooth1324 and sensing subunit 1322 can also be worn. The sensing subunit 1322can include a magnet 1330 and a magnetic sensor 1332 that detects themagnetic field generated by the magnet 1330. In some embodiments, whenthe appliance 1328 is worn by the patient, the presence of theferromagnetic target 1326 alters the characteristics of the generatedmagnetic field. The monitoring device 1320 can include a processor (notshown) configured to determine whether the appliance 1328 is being wornbased on the sensing data produced by the magnetic sensor 1332.Optionally, the processor and other components of the monitoring device1320 can also be integrated into the attachment device. Thisimplementation can reduce the costs of the device 1320, since only therelatively low cost ferromagnetic target would be replaced with each newappliance. FIG. 13C illustrates a monitoring device 1340 using magneticsensing, in accordance with embodiments. The monitoring device 1340includes a sensing subunit 1342 integrated into an attachment devicecoupled to a tooth 1344 in a patient's jaw (e.g., upper or lower jaw)and a ferromagnetic target 1346 (e.g., a metal plate) integrated into anintraoral appliance 1348 worn on the same jaw. The appliance 1348 caninclude a cavity shaped to receive the tooth 1344 and the sensingsubunit 1342. The sensing subunit 1342 can include a magnet and amagnetic sensor that detects the magnetic field generated by the magnet.In some embodiments, when the appliance 1348 is worn by the patient, thepresence of the ferromagnetic target 1346 alters the characteristics ofthe generated magnetic field. The monitoring device 1340 can include aprocessor (not shown) configured to determine whether the appliance 1348is being worn based on the sensing data produced by the magnetic sensor.Optionally, the processor and other components of the monitoring device1340 can also be integrated into the attachment device, thus reducingcost when multiple appliances are used.

Alternatively or in combination, a monitoring device can use a magnet todirectly activate a magnetic sensor. For example, a magnet can beattached to an intraoral tissue, such as a tooth surface. The monitoringdevice can include a magnetic sensor (e.g., a magnetic reed sensor orswitch) integrated into an intraoral appliance such that when theappliance is worn, the magnet activates the sensor. In alternativeembodiments, the locations of the magnet and magnetic sensor can beswitched, such that the magnetic sensor is attached to the intraoraltissue and the magnet is integrated into the appliance. Optionally, themagnet can be integrated into a first intraoral appliance worn on apatient's jaw (e.g., upper or lower jaw) and the magnetic sensor can beintegrated into a second intraoral appliance worn on the opposing jaw,such that when both appliances are worn, the magnet activates thesensor.

Alternatively or in combination, a monitoring device can utilize two ormore magnets that interact with each other (e.g., by exerting magneticforces on each other), and a sensor that detects the interaction betweenthe magnets. For example, the sensor can be a mechanical switch coupledto a magnet and actuated by magnetic forces exerted on the magnet. Asanother example, the sensor can be configured to detect thecharacteristics (e.g., magnitude, direction) of the magnetic forceexerted on a magnet by the other magnets. The magnets and sensor caneach be independently integrated in an appliance or coupled to a toothor other intraoral tissue.

FIGS. 14A and 14B illustrate a monitoring device 1400 using a pluralityof magnets, in accordance with embodiments. The device 1400 includes asensing subunit 1402 integrated into a first intraoral appliance 1404worn on a patient's jaw (e.g., upper or lower jaw). The sensing subunitincludes a first magnet 1406 coupled to a force sensor 1408. A secondmagnet 1410 is integrated into a second intraoral appliance 1412 worn onthe opposing jaw. The force sensor 1408 can measure the magnetic forcebetween the first magnet 1406 and the second magnet 1410, which variesaccording to the distance between the magnets. The monitoring device1400 can include a processor (not shown) configured to determine whetherthe appliances are being worn based on the measured force. In someembodiments, the magnetic force can also be used to generate power formonitoring device 1400.

Alternatively or in combination, the monitoring devices of the presentdisclosure can include one or more force and/or pressure sensors fordetecting appliance usage. For example, the monitoring device caninclude a force- and/or pressure-dependent resistive material, such as afilm or sheet. The resistive material can be positioned between two thinelectrodes in an intraoral appliance, and the resistance of the materialmay increase or decrease as force and/or pressure is exerted on thematerial, e.g., by the interaction between the teeth and the appliance.Other types of force and/or pressure sensors include strain gauges andpiezocrystal sensors. In some embodiments, the monitoring devicedetermines whether the patient is wearing the appliance based on theforce and/or pressure measurements obtained by the force and/or pressuresensors. The measurement data may be indicative of the force and/orpressure between the appliance and an intraoral tissue, such as one ormore of the patient's teeth. Optionally, the measurement data can bebased on the force and/or pressure between the appliance and one or moreattachment devices mounted on the patient's teeth. The monitoring devicecan process the data to determine whether the measured force and/orpressure are within the expected range corresponding to the patientwearing the appliance.

A monitoring device can include a single force and/or pressure sensor,or a plurality of force and/or pressure sensors. The sensors can bepositioned at any location in the appliance, such on an inner surface,an outer surface, a buccal surface, a lingual surface, an occlusalsurface, a mesial portion, a distal portion, a gingival portion, or acombination thereof. In some embodiments, the sensors are positioned tobe near certain teeth when the appliance is worn. In embodiments wherethe appliance is an orthodontic appliance, the sensors can be positionednear teeth to be repositioned, e.g., at locations where the appliance isexpected to exert force on the teeth. For example, if the appliance isshaped to engage an attachment device mounted on a tooth in order toexert force onto the tooth, a force and/or pressure sensor can belocated at or near the location of engagement between the appliance andthe attachment device.

FIG. 15 illustrates a monitoring device 1500 configured to measure forceand/or pressure between an intraoral appliance 1502 and the patient'steeth, in accordance with embodiments. The device 1500 includes aplurality of pressure and/or force sensors 1504 (e.g.,pressure-dependent resistive films) electrically coupled (e.g., viaprinted wires 1505 or other connecting elements) to a controller 1506.The plurality of pressure and/or force sensors 1504 can be patterned onthe inner surface of the appliance 1502 so as to generate sensor dataindicative of the pressure and/or force between the appliance 1502 andthe patient's teeth. In some embodiments, the appliance 1502 includes aplurality of teeth receiving cavities and the pressure and/or forcesensors 1504 are located on the buccal, lingual, and/or occlusalsurfaces of the cavities. The controller 1506 can include components(e.g., as previously described with respect to FIG. 3) configured toprocess the sensor data to determine whether the appliance 1502 is beingworn. Optionally, the controller 1506 can include a wireless antenna1508 for transmitting the sensing data and/or processing results to aremote device, as described herein.

FIGS. 16A and 16B illustrate a monitoring device 1600 configured tomeasure force and/or pressure between an intraoral appliance 1602 andone or more attachment devices 1604 on a patient's teeth 1606, inaccordance with embodiments. The device 1600 includes a plurality ofpressure and/or force sensors 1608 (e.g., pressure-dependent resistivefilms) electrically coupled to a controller 1610. The plurality ofpressure and/or force sensors 1608 can be patterned on the inner surfaceof the appliance 1602 so as to generate sensor data indicative of thepressure and/or force between the appliance 1602 and the attachmentdevices 1604 on the patient's teeth 1606. In some embodiments, theappliance 1602 includes a plurality of teeth receiving cavities formedwith one or more receptacles 1612 to receive the correspondingattachment devices 1604 on the patient's teeth, and the pressure and/orforce sensors 1608 can be positioned the inner surface of one or morereceptacles 1612. The controller 1610 can include components (e.g., aspreviously described with respect to FIG. 3A) configured to process thesensor data to determine whether the appliance 1602 is being worn.

Any of the apparatuses (e.g., monitoring devices) described herein maybe configured to determine mechanical impedance of the teeth and/orintraoral appliance. For example, any of the apparatuses describedherein may be configured to derive a mechanical impedance of a tooth,multiple or groups of teeth, and/or the appliance. Generally, mechanicalimpedance may be referred to as the resistance to motion given anapplied force:

Z(w) = F(w)/v(w)

Where F=force, v=velocity and w=angular frequency.

FIG. 16C illustrates one example of a section through an intraoralappliance 977 (showing in this example as an aligner) including a motionsensor 971 (such as an accelerometer) and one or more force sensors 969,969′, 969″. Alternatively or additionally, one or more of the motionsensor and force sensor(s) may be positioned directly on the teeth(including on an attachment adapted to secure the intraoral appliance tothe teeth) and may communicate with a processor/analysis engine,battery, communications circuitry, etc. on the aligner.

The processor/analysis engine may then use the motion (e.g.,acceleration) data over time, an example of which is shown in FIG. 16D,and corresponding force data over time, an example of which is shown inFIG. 16E, and may correlate this data to estimate mechanical impedance.

Alternatively of additionally, the system may estimate mechanicalimpedance based on underdamped second order system (e.g., as alogarithmic decrement of an underdamped second order system). In thiscase, the apparatus may be configured to measure the teeth (and/orappliance) response to a perturbing force, such as an input vibration orforce applied to the teeth. For example, the apparatus may be configuredto measure the free vibration response to a mechanical impulse input.The apparatus may then determine the peak-to-peak decay of theunderdamped oscillation and the period of the system; from these values,the apparatus may then derive the damped natural frequency, the naturalfrequency, and a damping ratio. In a second order system, these valuesmay define the impedance.

For linear systems, the apparatus may fit parameter of a parametricmodel of the mechanical impedance to a measured bode plot. Fornon-linear system, the apparatus may use generalized frequency responsefunctions to analyze non-linear systems (e.g., forced vibrationsresponse, sinusoidal frequency sweeps, etc., including machinelearning).

For example, FIG. 16F shows a side view of another example of anapparatus for measuring mechanical impedance of a tooth or teeth. Inthis example, a plurality of attachments 982 are used to secure anorthodontic appliance (e.g., aligner 989) to the teeth. The alignerincludes a processor 991, wireless communication circuitry, and mayinclude additional hardware, software and/or firmware for detectingsensor data to determine mechanical impedance of the teeth and/oraligner. The attachments may include one or more sensors, includingmotion (e.g., accelerometers) and/or force sensors; these one or moresensors may communicate directly (e.g., via electrical contact) with theprocessor 991 on the aligner.

In FIG. 16F, this configuration may be used as described above, and/ormay be used to determine a frequency response to an applied inputsignal. For example, any of these apparatuses may include an actuator toapply a vibration or force input to the teeth (e.g., a vibration motor,miniature piston, etc.). The force applied by the actuator may bemeasured or estimated and used in conjunction with the detected response(e.g., motion/acceleration data). Alternatively, the apparatus my takeinto account naturally occurring force inputs (e.g., masticatoryforces), and may measure or estimate them; as mentioned above, using oneor more force sensors. The force data as well as the responsemovement/acceleration data may be used to determine mechanicalimpedance.

The resulting mechanical impedance data may then be used to assess thehealth of the tooth movement.

Alternatively or in combination, the monitoring devices described hereincan include one or more gas flow sensors configured to detect whetherthe intraoral appliance is being worn based on intraoral airflow. Forinstance, the gas flow sensor can be a hot-wire anemometer configured tomeasure airflow associated with breathing, mastication, speech, snoring,and the like. The embodiments herein can also incorporatemicrofluidic-based gas flow sensors, as desired. Optionally, gas flowsensors can also be used to measure airflow to determine whether thepatient is experiencing a sleep apnea event. For example, the monitoringdevice can determine whether the measured airflow pattern is similar toairflow patterns that occur when the patient is experiencing sleepapnea. This approach can be used in embodiments where the intraoralappliance is a sleep apnea treatment appliance (e.g., a mandibularadvancement device), for example. FIG. 17A illustrates a monitoringdevice 1700 including a gas flow sensor 1702, in accordance withembodiments. The sensor 1702 is integrated into an intraoral appliance1704. In some embodiments, the sensing portion of the sensor 1702 (e.g.,a wire or conductor) extends from the appliance 1704 (e.g., a lingualsurface) so as to be exposed to intraoral airflow. The sensing dataobtained by the sensor 1702 can be processed and analyzed by othercomponents of the monitoring device 1700 (e.g., controller 1706) inorder to determine appliance usage and/or whether patient isexperiencing a sleep apnea event.

FIG. 17B illustrates a monitoring device 1720 including a gas flowsensor 1722, in accordance with embodiments. The device 1720 can besubstantially similar to the device 1700, except that the sensor 1722extends across the opposite sides of the appliance 1724 such that thesensing portion is located near the middle of the intraoral airflow.This approach may provide improved sensing accuracy.

FIG. 17C illustrates a monitoring device 1740 including a gas flowsensor 1742, in accordance with embodiments. The device 1740 can besubstantially similar to the device 1720, except that the sensor 1742extends only from one side of appliance 1744. This approach may reducepatient discomfort.

Alternatively or in combination, a monitoring device can include one ormore motion sensors configured to detect appliance usage based onmovements of one or both of the patient's jaws. Examples of such motionsensors include accelerometers, gyroscopes, piezoelectric film vibrationsensors, gravity sensors, and microwave emitters and receivers. Themotion sensors can be integrated into an intraoral appliance worn on apatient's upper or lower jaw, or can be distributed across an applianceworn on the upper jaw and an appliance worn on the lower jaw. In someembodiments, the motion sensors are configured to generate datarepresentative of the patient's jaw movement patterns, and themonitoring device processes and analyzes the movement patterns (e.g.,using power spectrum and/or kinematic analysis) to determine whether thepatterns indicate that the appliance(s) are being worn. Optionally, themonitoring device can distinguish jaw movement patterns associated withdifferent oral activities (e.g., mastication, grinding, speech, etc.).

FIG. 18 illustrates a monitoring device 1800 using motion sensing, inaccordance with embodiments. The device 1800 includes one or more motionsensors 1802 integrated into a first intraoral appliance 1804 worn on apatient's jaw (e.g., upper or lower jaw). In some embodiments, themotion sensors 1802 include one or more magnetometers that detect themagnetic field generated by a magnet 1806 integrated into a secondintraoral appliance 1808 worn on the opposing jaw. For instance, thedevice 1800 can include two multi-axis magnetometers used to obtain asix-axis measurement of the relative movements of the upper and lowerjaws. In alternative embodiments, rather than using the magnet 1806, themagnetometer(s) 1802 can be used to measure the angle of the patient'sjaw relative to the earth's magnetic field, and the angle data can beused to determine whether the appliance is being worn. The motion datagenerated by the motion sensor(s) 1802 can be used to track jaw movementpatterns in order to determine whether the appliances are currentlybeing worn. Other types of motion sensors 1802 can also be used, such asaccelerometers, gravity sensors, gyroscopes, or microwave emitters andreceivers.

Alternatively or in combination, a monitoring device can include one ormore temperature sensors, such as sensors detecting temperature based oninfrared radiation, conductive thermistor-based sensors, and the like.The motion detector can determine appliance usage based on whether themeasured temperature is within the range of body temperature, e.g., oralcavity temperature. Optionally, this determination can involve comparingthe measured temperature with ambient temperature measurements obtainedwhile the appliance is not being worn. In some embodiments, thetemperature data is recorded as the raw temperature value.Alternatively, the temperature data can be recorded in binary form(e.g., whether the temperature is within the range of body temperatureor not), for example, to save memory space.

Alternatively or in combination, a monitoring device can include one ormore strain gauges (e.g., resistive or MEMS-based) to detect the stressand/or strain at one or more locations in the intraoral appliance. Themonitoring device can determine whether the measured stress and/orstrain values are within the expected ranges for appliance usage. Themonitoring device can store the actual stress and/or strain values, orcan store just binary data indicating whether or not the appliance isbeing worn.

Alternatively or in combination, a monitoring device can include one ormore pH sensors configured to measure the pH values of fluids (e.g.,saliva) in the surrounding environment. The monitoring device candetermine whether the appliance is being worn based on whether themeasured pH values are within the expected pH range for human saliva,for example.

Alternatively or in combination, a monitoring device can include one ormore conductivity sensors configured to measure the conductivity offluids (e.g., saliva) in the surrounding environment. The monitoringdevice can determine whether the appliance is being worn based onwhether the measured conductivity is within the expected range for humansaliva, for example. In some embodiments, the conductivity can bemeasured over a period of time. This approach can be used to prevent themonitoring device from being deceived by immersion into saliva-mimickingfluids, since the conductivity of human saliva may vary over time basedon the body's physiological activities.

Alternatively or in combination, a monitoring device can include one ormore humidity sensors configured to detect contact with intraoral fluids(e.g., saliva). The monitoring device can determine whether theappliance is being worn based on whether the measured humidity is withinthe expected humidity range for the intraoral cavity, for example.

The monitoring devices described herein may be used to measure healthinformation for the patient alternatively to or in combination withdetecting appliance usage. Such monitoring devices can include one ormore physiological sensors, such as electrocardiography sensors,bio-impedance sensors, photoplethysmography sensors, galvanic skinresponse sensors, or combinations thereof. For example, aphotoplethysmography sensor can be used to measure blood volume changesin the patient's intraoral tissues such as the cheeks or gingiva. Asanother example, a galvanic skin response sensor can be used to measurethe conductivity of intraoral tissues, which may vary based on theminerals released onto the outer tissue surfaces from glands, forexample. In some embodiments, the monitoring devices described hereinare configured to differentiate between sensor data indicative ofappliance usage and sensor data produced by other types of patientinteractions with the appliance (e.g., the appliance being held in apatient's hand). Such differentiation can be accomplished by trainingthe monitoring device to distinguish between data patterns indicative ofappliance usage and data patterns produced by other interactions, e.g.,based on a training data set prior to actual patient monitoring and/ordata generated during monitoring. Alternatively or in combination, thisdifferentiation can be performed by other devices besides the monitoringdevice, e.g., by an external processor performing post-processing on thedata obtained by the monitoring device.

FIG. 19 illustrates a method 1900 for monitoring usage of an intraoralappliance, in accordance with embodiments. The method 1900 can beperformed using any embodiment of the systems and devices describedherein. In some embodiments, some or all of the steps are performedusing a processor of a monitoring device operably coupled to anintraoral appliance. Alternatively or in combination, some or all of thesteps can be performed by a processor of a device external to thepatient's intraoral cavity, e.g., a separate computing device or system.

In step 1910, sensor data is received from one or more sensors operablycoupled to an intraoral appliance. The one or more sensors can includeany of the sensor types described herein, including but not limited totouch or tactile sensors (e.g., capacitive, resistive), proximitysensors, audio sensors (e.g., microelectromechanical system (MEMS)microphones), color sensors (e.g., RGB color sensors), electromagneticsensors (e.g., magnetic reed sensors, magnetometer), light sensors,force sensors (e.g., force-dependent resistive materials), pressuresensors, temperature sensors, motion sensors (e.g., accelerometers,gyroscopes), vibration sensors, piezoelectric sensors, strain gauges, pHsensors, conductivity sensors, gas flow sensors, gas detection sensors,humidity or moisture sensors, physiological sensors (e.g.,electrocardiography sensors, bio-impedance sensors, photoplethysmographysensors, galvanic skin response sensors), or combinations thereof. Thesensor(s) can be physically integrated with (e.g., coupled to, embeddedin, formed with, etc.) the intraoral appliance, or can be positioned inthe intraoral cavity (e.g., attached to a tooth) so as to interact withthe intraoral appliance. The sensor data can be indicative of whetherthe appliance is currently being worn in the patient's mouth, inaccordance with the embodiments described herein.

In step 1920, the sensor data is processed to determine whether theappliance is being worn. For example, the processing step can involvedetermining whether the sensor data matches a pattern and/or fallswithin a range of values indicating that the appliance is being worn.Alternatively or in combination, the processing step can involvedetermine whether the sensor data is different from a pattern and/orlies outside a range of values indicating that the appliance is notbeing worn. Optionally, the processing step can involve associating thesensor data with a timestamp representing when the data was obtainedsuch that temporal appliance usage information can be determined. Theprocessed sensor data can include appliance usage information indicatingwhether the appliance is currently being worn, the duration of applianceusage, and/or the date-time the appliance was in use. In someembodiments, step 1920 can alternatively or additionally involveprocessing the sensor data to determine patient health information, asdiscussed herein.

In step 1930, the sensor data generated in step 1910 and/or processedsensor data generated in step 1920 is optionally transmitted to a remotedevice. The remote device can be a mobile device (e.g., smartphone),personal computer, laptop, tablet, wearable device, cloud computingserver, or the like. Step 1930 can be performed using wireless or wiredcommunication methods, as desired. Step 1930 can be performedautomatically (e.g., at predetermined time intervals) or in response toinstructions received from the remote device (e.g., a command totransmit the sensor data and/or appliance usage).

The monitoring devices described herein can be physically integratedinto an intraoral appliance in a variety of ways. In some embodiments,the monitoring device is integrated into the appliance during or afterfabrication of the appliance. For example, the monitoring device can beattached to an appliance using adhesives, fasteners, a latchingmechanism, or a combination thereof after the appliance has beenfabricated. Optionally, the appliance can be formed with complementaryfeatures or structures (e.g., recesses, receptacles, guides, apertures,etc.) shaped to receive and accommodate the monitoring device orcomponents thereof.

In some embodiments, a monitoring device is coupled to the appliance asa prefabricated unit during or after fabrication of the appliance, suchas by being inserted and sealed into a receptacle in the appliance,attached to an appliance (e.g., by a latching mechanism, adhesive,fastener). Alternatively, the monitoring device can be assembled in situon the appliance during or after appliance fabrication. For instance, inembodiments where the appliance is manufactured by direct fabrication(e.g., 3D printing), the monitoring device can be printed simultaneouslywith the appliance, inserted into the appliance during fabrication, orafter assembled the appliance has been fabricated. Optionally, some ofthe monitoring device components may be prefabricated and othercomponents may be assembled in situ. It shall be appreciated that thevarious fabrication methods described herein can be combined in variousways in order to produce an appliance with integrated monitoring devicecomponents.

FIGS. 20A through 20D illustrate a method for fabricating an intraoralappliance with an integrated monitoring device, in accordance withembodiments. The method can be applied to any embodiment of themonitoring devices and appliances described herein, and can be used incombination with any of the other fabrication methods described herein.In a first step (FIGS. 20A (top view) and 20B (side view)), aprefabricated monitoring device 2000 is coupled to a positive model 2002of a patient's dentition. The monitoring device 2000 can be attachedusing an adhesive and/or a mechanical fastener, for example. Optionally,the monitoring device 2000 can be hermetically sealed prior to beingattached to the model 2002. In a second step (FIG. 20C), a material isformed (e.g., thermoformed) over the monitoring device 2000 and model2002 so as to produce an appliance shell 2004. In a third step (FIG.20D), the mold 2002 is removed, resulting in an appliance shell 2004with an embedded monitoring device 2000. Optionally, the monitoringdevice 2000 can be encapsulated using a biocompatible adhesive 2006(e.g., a UV-curable glue), a layer of material, or other sealingelement.

FIGS. 21A through 21C illustrate a method for fabricating an intraoralappliance with an integrated monitoring device, in accordance withembodiments. The method can be applied to any embodiment of themonitoring devices and appliances described herein, and can be used incombination with any of the other fabrication methods described herein.In a first step (FIG. 21A), an appliance 2100 is formed (e.g.,thermoformed) over a positive model 2102 of a patient's dentition. In asecond step (FIG. 21B), a prefabricated monitoring device 2104 isattached to the appliance 2100, e.g., using an adhesive layer 2106and/or fastener, and a thermoplastic material 2108 is attached to theouter surface of the monitoring device 2104. In a third step (FIG. 21C),the thermoplastic material 2108 is thermoformed so as to form a coverencapsulating the monitoring device 2104 into the appliance 2100. Thepositive model 2102 can be removed e.g., before or after the third step.

Alternatively or in combination, the method can involve forming apositive geometry corresponding to the geometry of the monitoring device2104 on the positive model 2102 (e.g., by 3D printing, CNC milling,etc.), such that the appliance 2100 is thermoformed with a receptaclefor the monitoring device 2104. The monitoring device 2104 can then beplaced and sealed into the receptacle.

Alternatively or in combination, an intraoral appliance with anintegrated monitoring device can be produced by fabricating theappliance (e.g., by indirect or direct fabrication), then attaching aprefabricated monitoring device to the fabricated appliance, e.g., usingadhesives, fasteners, a latching mechanism, etc. Optionally, themonitoring device can be hermetically sealed (e.g., by molding) beforebeing attached to the appliance.

Alternatively or in combination, an intraoral appliance with anintegrated monitoring device can be fabricated by coupling flexibleand/or printed components of a monitoring device onto the applianceduring or after forming the appliance. The components can be coupled invarious ways, such as thermoforming, laminating, adhesives, coating, andso on.

Alternatively or in combination, an intraoral appliance with anintegrated monitoring device can be fabricated by 3D printing a base forthe monitoring device, then building up the electronic components forthe monitoring device onto the base. In some embodiments, the base isshaped to conform to the geometry of the tooth receiving cavity and/ortarget tooth where the monitoring device will be located. The 3D printedportions of the monitoring device can be shaped to lie flush with thesurface of the appliance to facilitate integration of the monitoringdevice with the appliance. Alternatively or in combination, an intraoralappliance with an integrated monitoring device can be fabricated byetching the surface of the appliance (e.g., using a masking process) andthen depositing conductive inks, stretchable materials, etc. onto theetched portions to build up the electronic components of the monitoringdevice (e.g., wires, connections, electrodes, etc.) on the appliance.

FIG. 22 is a simplified block diagram of a data processing system 2200that may be used in executing methods and processes described herein.The data processing system 2200 typically includes at least oneprocessor 2202 that communicates with one or more peripheral devices viabus subsystem 2204. These peripheral devices typically include a storagesubsystem 2206 (memory subsystem 2208 and file storage subsystem 2214),a set of user interface input and output devices 2218, and an interfaceto outside networks 2216. This interface is shown schematically as“Network Interface” block 2216, and is coupled to correspondinginterface devices in other data processing systems via communicationnetwork interface 2224. Data processing system 2200 can include, forexample, one or more computers, such as a personal computer,workstation, mainframe, laptop, and the like.

The user interface input devices 2218 are not limited to any particulardevice, and can typically include, for example, a keyboard, pointingdevice, mouse, scanner, interactive displays, touchpad, joysticks, etc.Similarly, various user interface output devices can be employed in asystem of the invention, and can include, for example, one or more of aprinter, display (e.g., visual, non-visual) system/subsystem,controller, projection device, audio output, and the like. Storagesubsystem 2206 maintains the basic required programming, includingcomputer readable media having instructions (e.g., operatinginstructions, etc.), and data constructs. The program modules discussedherein are typically stored in storage subsystem 2206. Storage subsystem2206 typically includes memory subsystem 2208 and file storage subsystem2214. Memory subsystem 2208 typically includes a number of memories(e.g., RAM 2210, ROM 2212, etc.) including computer readable memory forstorage of fixed instructions, instructions and data during programexecution, basic input/output system, etc. File storage subsystem 2214provides persistent (non-volatile) storage for program and data files,and can include one or more removable or fixed drives or media, harddisk, floppy disk, CD-ROM, DVD, optical drives, and the like. One ormore of the storage systems, drives, etc. may be located at a remotelocation, such coupled via a server on a network or via theinternet/World Wide Web. In this context, the term “bus subsystem” isused generically so as to include any mechanism for letting the variouscomponents and subsystems communicate with each other as intended andcan include a variety of suitable components/systems that would be knownor recognized as suitable for use therein. It will be recognized thatvarious components of the system can be, but need not necessarily be atthe same physical location, but could be connected via variouslocal-area or wide-area network media, transmission systems, etc.

Scanner 2220 includes any means for obtaining a digital representation(e.g., images, surface topography data, etc.) of a patient's teeth(e.g., by scanning physical models of the teeth such as casts 2221, byscanning impressions taken of the teeth, or by directly scanning theintraoral cavity), which can be obtained either from the patient or fromtreating professional, such as an orthodontist, and includes means ofproviding the digital representation to data processing system 2200 forfurther processing. Scanner 2220 may be located at a location remotewith respect to other components of the system and can communicate imagedata and/or information to data processing system 2200, for example, viaa network interface 2224. Fabrication system 2222 fabricates appliances2223 based on a treatment plan, including data set information receivedfrom data processing system 2200. Fabrication machine 2222 can, forexample, be located at a remote location and receive data setinformation from data processing system 2200 via network interface 2224.

Examples

Any of the monitoring apparatuses described herein, which may bereferred to as ECI's and/or data loggers, may be wirelessly connected orconnected by a wire (“wire-connected”), or both. For example, when awired communication with a monitoring apparatus is used, the apparatusmay be connected via one or more pins/contacts on an outer surface ofthe apparatus, either when worn and/or attached to an orthodonticappliance (such an aligner) or after removing from the appliance. Datacommunication with the monitoring device may be enabled via a readerhaving one or more mechanical probes that may act as electrical contactswith electrodes/pads in or on the monitoring apparatus. For example, theprobes may be located in a case or housing for holding the appliance,which can then separately communicate with a hand-held electronicsdevice such as a smartphone, via Bluetooth. Thus, for example, themonitoring apparatus may connect via a wired connection to a case, andthe case may then transmit the data (either raw or unmodified data ormodified, analyzed and/or formatted data) to a separate handheld device,such as a smartphone.

The monitoring apparatus may include one or more (e.g., a plurality of)connection pads which may be encapsulated in a self-healing polymer thatopens upon insertion of probes and retract to original shape uponremoval of the probes providing water sealing. Alternatively oradditionally, the connection pads may be exposed out of ECI butgrounded/disabled when aligner and/or ECI is in a mouth or in contactwith water/saliva. Upon being energized by reader probes, the ECI padsmay switch to communication mode.

Any of the monitoring apparatuses described herein may also beconfigured to be stored in an inactive configuration, in which some orall of the internal contacts are disabled (e.g., disabling theconnection between the battery and the processor or other components bya physical break, gap, pin, barrier, etc. that may be removed (e.g.,connecting/reconnecting the power source to the circuitry) manually orautomatically prior to use, including prior to removing from a case orpackaging, prior inserting the device into a subject's mouth, prior toconnecting the monitoring apparatus to a dental appliance, etc. Forexample, the apparatus may include mechanical activation of themonitoring apparatus via removing a tiny pin.

In any of the ECI apparatuses described herein, a mechanicalactivation/deactivation connection may be used, as described above. Anyof these ECIs (e.g., “data loggers”) may be configured for wired (directmechanical/electrical) connection to a reader. The ECI may includeinternal circuitry (e.g., an ASIC, and/or any of the circuitry describedabove) one or more sensors, memory, etc.) and a battery that areenclosed or at least partially enclosed, in a housing. A plurality ofdata pads may be present outside of this housing, so that an electricalconnection can be made to the internal circuitry. As mentioned, theentire device, including the pads, may be covered by a protectiveelastomer (e.g., a self-healing elastomer). This elastomer may be anyappropriate material, typically a biocompatible, electrically insulativematerial that is self-healing or self-sealing after being pierced.

The monitoring apparatus (ECI) operation may be initiated by the user,e.g., patient, dental technician, etc., including mechanicallyactivating using a pin, rod, or the like. For example, prior to use ofthe ECI, the user may remove an activation rod. When in place, the rodmay breaks connection between the battery and the circuit, ensuring zerooff current to the ECI circuitry (e.g., ASIC). When the activation rodis removed, the battery may be connected to the ECI ASIC, initiating thedata logging sequence. During operation, the ECI ASIC may acquire rawsensor data, as described above. For example, the apparatus may acquireraw capacitance and temperature data at 10 minute intervals, and storeeach sample in memory (e.g., EEPPROM). The sampling intervals may becounted as individual events, translated into desired time intervaldisplay format by the intermediate interface device. Thus, any of theapparatuses described herein may have reduced size/footprint, byeliminating the need for a real time clock and related EEPROM memory.The ECI may include a housing (packaging) consists of a rigid materialholding the the internal circuitry and battery part of the assembly, andmay also include an elastomeric coating over the housing and the datapads. Data may be retrieved from the devices even when the battery iscompletely depleted, such as if the patient fails to deliver the ECIback to the dental professional (e.g., orthodontist) within the smallbattery's lifetime. As an alternatively variation, the operation ofmechanical activating mechanism may be reversed from which is describedabove, so that the ECI apparatus is activated by inserting, rather thanremoving, an activating rod, pin, etc.

In other variations, a similar mechanical control or switch may beprovided by including a spring contact that is held open by a magneticfield, rather than using an activating rod/pin. In this example, theapparatus may be activated by removing it from a package; when in thepackaging a permanent magnet (e.g., built into the packaging/housing)may hold a spring contact away from the circuitry, disconnecting thebattery from the rest of the circuitry (e.g., ASIC), breaking theconnection between the battery and the rest of the circuit, alsoensuring zero off-current to the circuitry. Removing the device from thepackaging may allow the spring contact to close, activating the datalogging sequence, so that the apparatus can acquire data (e.g.,capacitance and/or temperature data at a continuous 10 min intervals,and store the data in the memory for later read-out from the data pads).

Although mechanical activation may be used in the context of anapparatus having data contact pads for making a wired connection, any ofthe apparatuses, including those configured to operate wirelessly, maybe configured to mechanical activation.

In addition, any of the ECI apparatuses described herein may beconfigured to be inserted/connected to an orthodontic appliance (such asan aligner) by the user or a dental professional. For example, FIG. 24illustrates an example of an ECI apparatus 2500 that can be insertedonto an aligner 2502. In this case, the ECI apparatus shown isconfigured for a wired connection (via the pads 2507), however wirelessECI apparatuses may be similarly configured for connection onto analigner 2502. The aligner may therefore include on or more retainingfeatures, as described above, including pins 2503, as shown in FIG. 24.In some variations, the retaining feature on the aligner may make themechanical connection between the battery and the circuitry. In somevariations, the pins may connect to one or more sensors on the aligner.The pins may penetrate an over molding material, which may be present onany of the variations (including the wireless and wired connectiondevices).

As mentioned, data may be retrieved from any of these apparatuses usingan intermediate interface device such as a housing or case. When the ECIapparatus is configured to make a wired connection, the intermediatedevice may be fitted with sharp probes to penetrate the over moldelastomer and make electrical contact with any data pads on the PCB. Theintermediate device may then retrieve, process, calibrate, and encryptthe data as needed, then transmit to a handheld device such as a smartphone, e.g., via Bluetooth. The data can then be displayed on thesmartphone or other display medium using custom applications software,which the patient and/or orthodontist may be able to download forexecution on the smartphone or other mobile device

In any of the variations described herein, the same pins can be used forconnecting and as a conductivity sensing probe for detection of salivamedium.

Although FIGS. 24 and 25 illustrate the connective pads as covered bythe over molding material, in some variations the connection pads may beexposed. For example, the connection pads may be exposed out of ECI butgrounded/disabled when Aligner and ECI are in the user's mouth or incontact with water/saliva. Upon being energized by reader probes the ECIpads may switch to a communication mode during which data may betransferred.

Any of the devices described herein may also or alternatively beconnected by a wireless connection. FIG. 25 illustrates one example ofan ECI prototype constructed as described herein, including one or moretemperature and capacitive sensors. In this example, the ECI 2603 isconnected to an aligner (shell 2601). In FIG. 25, the prototype isrelatively large; it may be much smaller in practice, for example, byreducing the size of the processor, sensors and other internalcomponents. For example the prototype shown in FIG. 25 may include aTexas Instruments FDC1004 capacitive-to-digital converter (with afootprint of 10×8 mm); this footprint may be significantly reduced insize, e.g., using QFN rather than SOP package. The data logger mayinclude an on-chip temperature sensing data logger (e.g., an NFC type,such as a THOR data logger). The exemplary prototype shown in FIG. 25may be wirelessly connected to an intermediate device, and therefore ahandheld electronics device such as a smartphone.

In any of the apparatuses described herein, the ECI may include acapacitive sensor, which may be configured to accurately determine whenthe apparatus is present on a tooth/teeth, rather than outside of themouth, even when submerged in water or other material that may mimicsaliva. For example, a prototype such as that shown in FIG. 25 was usedas a proof-of-concept to show that capacitance data may be used todetermine when an oral appliance was present in the mouth of the user,rather than just submerged (or outside of the mouth). In FIG. 26,capacitance (and temperature) was recorded using the device of FIG. 25every 5 minutes for fifty-four hours, while subjecting the device todifferent conditions and looking at the capacitance. As shown, theapparatus is able to distinguish between being worn (“touched” 2703) andsubmerged in saline (“submerged 2705). As discussed above, thecapacitive sensor configuration may be configured to be mutualcapacitance measurements or self-capacitance measurements (see, e.g.,FIG. 27, left and right, respectively). The capacitance sensor maysaturate, however using the proper frequency range and/or ground sizemay permit the capacitance detector circuitry to distinguish betweensaturation due to being in the mouth versus being submerged in a fluid.

For example, FIGS. 28 and 29A-29B illustrate one example of an ECI thatis configured to distinguish between being worn and other conditionsthat may otherwise provide capacitive signals similar to those providedwhen in a fluid solution but not worn. In FIG. 28, the ECI 2901 is shownworn on a subject's teeth 2905 as part of an aligner 2903. The alignerin this case is shown having two sensing electrodes (A and B). The firstelectrode (A) is configured to be in close proximity to a crown of atooth when the aligner is worn. The second (B) is configured to be ‘far’proximity to the crown of the tooth when worn. FIG. 29A shows aschematic of the ECI, including the A and B sensing electrodes. FIG. 29Billustrates how capacitive signals from these sensing electrodes may beused to distinguish when the device is actually being worn in the mouth,versus when the ECI is out of the mouth or submerged in a saliva-likeenvironment. The logic used to distinguish these conditions may be usedto determine a more accurate ‘worn’ or ‘not worn’ metric that may beoutput by the ECI or by software/firmware/hardware in communication withthe ECI (e.g., from an application software running on a smartphone,etc.). In FIG. 29B, the signal from the A contact sensor is shownaligned with the signal from the B contact sensor. In this case, threeconditions are shown, as well as rough signal amplitudes. When the ECIis out of the mouth, the signal on the A sensing electrode is low;similarly, the signal on the B sensing electrode is low. When the deviceis worn as shown in FIG. 28, the signal on the A sensing electrode ishigh (greater than a threshold amount, ACR), and the signal on the Bsensing electrode is higher than when out of the mouth, but lower than athreshold (BCR). When the device is submerged in water, however, thesignals on both the A sensing electrode and B sensing electrode arehigh, above the ACR and BCR thresholds. Thus, the apparatus maydistinguish between in, out and submerged cases, by rejecting readingswhen A>ACR and B>BCR as false positives. When both A and B are belowtheir thresholds the device is out of the mouth, and when the A signalis above threshold but the B signal is below threshold, the device maybe determined to be in the users mouth.

FIGS. 30A-30C illustrate another example of a method for discriminatingbetween these conditions (in mouth, out of the mouth, and submerged). Inthis example, the apparatus may again include a pair of sensingelectrodes “A” 3001 and “B” 3003, however they are positioned on eitherside of a tooth on the aligner, and a complex impedance measure, Z, maybe taken between them. This “guard” electrode configuration may useshort detection pulses to distinguish between false positive readings.This signal may be used in conjunction with proximity sensing toincrease the specificity of the detection. The placement of the sensingelectrodes may be optimized to minimize the likelihood of falsenegatives (e.g., shorting by saliva). For example, the electrodes may beplaced at the ends of the arch, as shown in FIG. 30C. In thisconfiguration, the complex impedance, Z, may be 0 when the electrodesare placed in water, rather than against the teeth. As shown in FIG.30D, when the proximity sensor shows that the real capacitance is low,the apparatus is out of the mouth; when the proximity sensor shown ahigh or moderately high capacitance, and the complex impedancemeasurement is low, the apparatus is likely submerged in a solution(e.g., of water), and thus these measurements can be rejected as falsepositives.

When the ECI apparatuses described herein wirelessly communicate data(e.g., data output) to a handheld device, such as a smartphone, anintermediate apparatus such as a case or container, which may holdeither just the ECI module or apparatus, and/or it may hold the ECIapparatus and an appliance (such as an aligner) to which the ECIapparatus is attached. FIGS. 31A-31D illustrate one example of acontainer that acts as an intermediary device, receiving near fieldcommunication signals from the ECI module, and transmitting thesesignals to a smartphone or other handheld device by Bluetooth. Becauseof the relatively small size of the ECI apparatus, any antenna componentused for wirelessly transmitting signals must also be small; this maypose a problem for directly communicating with a smartphone or otherapparatus, as it may be difficult to align the antenna of the ECIapparatus with the antenna of a smartphone or other hand-heldelectronics device. In this case, a case or holder such as that shownand described in FIGS. 31A-31D may be used to both securely hold theappliance and ECI and to transfer any data recorded by the ECI from theECI to the case and then on to a mobile devices such as a smartphone,transferring the data first as NFC from the ECI to the intermediatecase, then as BLE from the intermediate case to the smartphone. The caseor other intermediate device may hold the ECI in a predeterminedposition, including in alignment with one or more antenna. Note thatdata may be transmitted between the ECI, case and mobile device in anongoing manner or sequentially (e.g., delaying transmission between thecase and the mobile device); delaying transmission may be helpful fordetermining when the receiving device (e.g., mobile device) is ready toreceive the data, and the intermediate device may hold onto the datauntil the receiving device indicates it is ready. In FIG. 31A, thealigner 3103 fits into the case 3101 so that the ECI 3105 is alignedwith a reader antenna 3107 for reliable transmission via NFC. Theintermediate device, such as a case, may be passive (e.g., transferringon the data) or it may be active, e.g., modifying, filtering,annotating, analyzing, averaging, etc. the data.

In general, when the ECI apparatus is configure to wirelessly transferdata, the near-field communication antenna (NFC antenna) may be a flatantenna, such as a trace antenna, and/or it may be a coil antenna. FIGS.34A and 34B illustrate a flat (trace) antenna and the user of such anantenna to transfer data from an appliance incorporating an ECI datarecorder. In FIG. 34A, the trace antenna is formed on a substrate (e.g.,PCB substrate) and forms a loop 3404 (or multiple loops) and connects toantenna circuitry 3402. The trace antenna produces a field that issubstantially transverse to the plane of the substrate. In FIG. 34B thealigner 3407 may be aligned with the attached ECI 3406 adjacent to theantenna loop 3404. In FIG. 34B, two separate NFC antennas are shown inalternative views of the ECI. In the upper portion, the ECI antenna is acoil antenna 3411; the antenna in the lower ECI is a trace antenna 3413.

FIG. 35A illustrates an enlarged view of a generic coil antenna (e.g., acoil wound around a ferrite rod) that may be used for NFC; FIG. 35Bshows an example of an ECI and reader, both of which use coil antenna.In FIG. 35B, the ECI antenna 3505 includes a ferrite core, as does thecoil antenna on the reader 3507. Any of the readers (includingintermediate devices such as holders, etc.) may use any appropriateantenna, including coil antennas and trace antennas. In FIGS. 34B and35B the readers may be used while the appliance (shown as an aligner) isattached to the ECI.

As mentioned, there is typically a size discrepancy between the NFCantenna in the ECI apparatus and the antenna in a phone (e.g.,smartphone) and other handheld electronics device. Thus, the energytransfer efficiency between a relatively large NFC loop antenna such asmay be present in a smartphone and the much smaller ECI loop antenna(e.g., typically only as large as a tooth width) maybe extremely low,including less than 1% due to the antenna size mismatch. Thus, it may bebeneficial to use an energy coupler, including as part of anintermediate device (e.g., booster, etc.) which may be configured as acase, mount, holder, or otherwise. FIGS. 36A-36C illustrates a passiveNFC energy coupler that may be used. In FIG. 36A, the circuit diagramillustrates the use of a NFC coupler 3603 between an ECI apparatus NFCantenna 3601 and the antenna of a smartphone 3605. Any appropriateantenna may be used as part of the NFC coupler, including a toroidferrite coupler 3607 having an air gap 3609 in the ferrite core, asshown in FIG. 36B; the ECI (or the NFC antenna of the ECI) may be placedwithin the air gap. FIG. 36C illustrate the overall system couplingprediction using an NFC coupler.

FIGS. 37A and 37B illustrate the use of an NFC to NFC coupler prototypethat may be used as an intermediate device. As shown in FIG. 37A, an ECIapparatus (shown schematically as having a coil antenna) 3701 ispositioned within range of an NFC antenna 3703, shown in this example acoil antenna having an air gap with a ferrite coil (e.g., a 6 mm loopantenna). The signal received from the NFC antenna is then retransmittedusing second antenna 3705 of the NFC coupler to transmit by NFC to aphone 3707 placed in range to the second, larger antenna 3711. As willbe described in FIG. 39, below, the first antenna may be matched to theECI antenna and the second antenna may be matched to the antenna in thephone. In addition, the NFC coupler apparatus may provide alignmentbetween the phone antenna and the second antenna 3711 and the ECIantenna and the first antenna, and may hold the phone and/or the ECIsecurely in the position. The prototype shown in 37B also includesindicates that additional circuitry (e.g. amplifiers, filters, etc.)3413 may be used to modify the data signal received from the ECI beforeit is passed on to the phone. In general, any signal processing may beperformed at this stage, or the signal may simply be passed. In oneexample a 3 dB attenuator is positioned between the first antenna 3703and the second antenna 2711.

FIG. 38A shows a prototype of the NFC coupler similar to thatschematically illustrated in FIGS. 37A and 37B. In FIG. 38, an alignerhaving an ECI is placed on the NFC coupler so that the ECI antenna isaligned with the NFC antenna of the NFC coupler (not visible in FIG.38). A phone receiving the signal passed on the NFC coupler ispositioned over the phone antenna region of the NFC coupler. FIG. 39shows a schematic circuit diagram of the apparatus of FIG. 38. In thisexample, a pair of shunts (C1, C2) and a series of capacitors (C3, C4)transform the inductive impedance of both of the NFC coupler coils to aresistive impedance at the center of the circuit, greatly eliminatingthe impedance mismatch losses in the system.

In addition to transfer of data from the ECI by an intermediate devicesuch as a case or other relay apparatus, in some variations, the ECI maybe configured (in some variations in conjunction with other systemcomponents, including hardware, software and/or firmware) for directtransfer of data from the ECI to a mobile, handheld device such as asmartphone (e.g., NFC to NFC communication or alternatively, NFC toBluetooth or other wireless protocol). For example, FIG. 32 illustratesa first example of a system for transmitting data directly from an ECIto a mobile handheld device. In FIG. 32, a marker or guide (e.g.,sticker, decal, phone cover/case, sleeve, etc.) may indicate a position3201 or location for placement of an ECI or aligner/appliance and ECI onthe phone 3203 to reliably transfer data (e.g., via NFC) from the ECIapparatus to the smartphone. In FIG. 32 the guide markings are part of adecal 3205.

In some variations the application software on the mobile device (e.g.,phone) may also provide guidance for alignment of the ECI, includingindicating on the screen where to place the ECI apparatus and/orappliance and ECI. The software may also indicate by visual, audio, orboth when the ECI is in good alignment, allowing the user tocorrect/adjust the alignment. For example, FIG. 33A illustrates anotherexample of direct communication between the ECI and a smartphone. Inthis example, the application software for data transfer from the ECI tothe phone 3301 indicates by displaying an alignment zone 3303 on thescreen of the phone where to position the ECI. In FIGS. 33B-33C, anadditional holder or interface 3305 to hold the ECI securely on thephone is shown, and FIG. 33C illustrates the use of the holder 3305 tohold the ECI on the optimal target for transfer of data. In thisexample, the data receiver is a mobile/handheld device (e.g.,smartphone) that may help align the ECI for transfer of the data, asillustrated in FIGS. 33B and 33C. In these illustrations, the screen ofthe mobile device shows a target that may indicate the position forplacement of the ECI relative to the mobile device for bestcommunication between the ECI (e.g., an antenna such as a NFC antenna)in the ECI and an antenna in the smartphone (such as an NFC antenna). Inthis example, the target (which is drawn as a bullseye, but may be anymarker or indicator 3303) is shown on the screen and the user maymanually align the target-matching portion of the ‘clip’ 3305 forpositioning opposite of the target 3303. This allows an ECI attached oron the clip (see top of FIG. 33C) to be held optimal alignment. Themobile device may determine the location of the target 3303 based on oneor more criterion, including the hardware (e.g., mobile device)configuration, model, etc., such as the known location of the antennawithin the device of a particular make and model that may be determinedby the application method (e.g., software) operating the mobile device(shown in FIGS. 33B and 33C as a “Find my Antenna” application method).In some variations, the application method may calculate the target 3303position based on feedback between the receiver (mobile device) antennaand the ECI device.

Other alignment mechanisms and techniques may also be used to alignand/or hold the ECI apparatus in communication with the phone forwireless transfer of data from the ECI to the smartphone. For example,in some variations a magnetic force may be used to attract the ECI to atarget location. Other mechanical alignment mechanisms may be used tosecure the ECI apparatus in alignment with the antenna region of thephone. For example, a phone case or cover (e.g., sleeve) may be usedthat includes a depression/holding region for aligning the ECI with theantenna of the phone. In some variations the mount/cover/sleeve mayinclude one or more pins to hold the ECI device in position.

As mentioned above, any of the apparatuses described herein (includingsystems) may communicate with a hand-held electronics device such asmartphone via control software running on the smartphone (or otherhand-held electronics). This application software may interface with theelectronic compliance indicator and may enhance wireless communicationsbetween the electronic compliance indicator (ECI) using NFC and BLEprotocols. The application can complement or supplement the ECI byincorporating mechanisms for encouraging compliance (e.g., incentives,gamification, etc.), and may also provide data processing,visualization, and/or sharing of the data from the ECI. An ECI apparatusmay generally record sensor data from patients wearing an orthodonticappliance such as an aligner. The data may be stored in physical memoryon the ECI and retrieved by another device, e.g., using NFC and BLEtechnologies as described above (or NFC and NFC), so that the smartphonemay retrieve the data. The smartphone application (app) may consist ofseveral components, some of which are described in FIGS. 41, 42 and 43.For example, in FIG. 41 schematically illustrates an NFC/BLEcommunication control. In addition, FIGS. 44, 45 and 46 schematicallyillustrate operational states of the ECI device, as well as control ofcommunication between the device and a remote processor (e.g.,smartphone).

Handling wireless communications and data transfer with the ECI may becoordinated by the application software. The application can post eventsto may include other elements of the application, for example: a homescreen or user interface (UI) manager that can respond to an event(e.g., a “CARD ACTIVATED” event, as shown in FIGS. 41-42, when the ECIis first turned on and receives confirmation back) to provide anotification to the user or launch a welcome or instructions screen;and/or a data analysis manager that can respond to data transfer (e.g.,an “UPDLOAD SUCCESS” in FIG. 43) events. The application software maygenerate displays, including graphs, and may look for patterns in thedata to improve accuracy/specificity/sensitivity of the compliance data.It may post events such as “LOW COMPLIANCE,” “HIGH COMPLIANCE,” etc.See, e.g., FIG. 40 (center), showing a user interface for an exemplaryapplication software including a smart compliance monitoring.

Some components of the application software may not exist or run locally(on the smart phone), but could run on a remote server. For example,data history and data analysis can be hosted on a remote server. In thiscase, the app may also have a component to upload and download data toand from this server.

The application software may help the user to manage the operation ofthe appliance and/or the ECI on the appliance, includingstarting/stopping timing/sensing/recording, and/or transferring datato/from the ECI, activating/de-activating the ECI, etc. Events that areposted from normal use can be used to complement or supplement the ECIsystem from the application software. For example, the applicationsoftware may manage notifications or reminders related to the applianceand/or ECI and/or can respond to an event (e.g., a “CARD ACTIVATED”event) by initiating a timer, which can post another event when itexpires. One possible response to this event may be to push anotification to the user to remind the user to connect the ECI device tothe phone. This notification can be an alarm, email, text message, etc.This service could also respond to a “LOW COMPLIANCE” by notifying otherconnected users (e.g., parents or doctors).

The application software may also coordinate an incentives system whichresponds to specific events related to wearing/using the orthodonticappliances described herein. For example, and application software mayinclude or operate a game with virtual rewards (e.g., coins, trophies,RPG elements “level up”/upgrade your smile, points, etc.), monetaryrewards (e.g., discounts, coupons, gift cards, etc.), and/ormotivational messages. For example when the “CARD ACTIVATED” eventoccurs by outputting->“You've activated your first aligner! You're onyour way to a happy healthy smile.” After a DOWNLOADED event, a specificmessage may be displayed or transmitted to the user depending on thedata, e.g., “great job wearing your aligners this week,” “just 2 morealigners to go!” or the like.

FIG. 42 illustrates a potential flow diagram for an application softwareas described herein for controlling NFC, including detecting the ECI.FIG. 43 illustrates a potential control diagram for an applicationsoftware controlling data processing.

An example of the operational states for an ECI device is shown in FIG.44, illustrating the interaction of the communication between the device(e.g., an appliance with monitoring sensors, shown as the ECI) and aremote processor such as a smartphone. In FIG. 44, the devicetransitions between various power down and logging states in which NFCis active or removed. Other possible states may include an active modein which logging is complete, and active mode with live measurements.

FIG. 45 illustrates the management of communications by the receivingprocessor, such as a smartphone, on which control logic (e.g., software)is operating; FIG. 45 illustrates one example of how the phone/receiverapp may behave and interact. For example, in FIG. 45, the smartphone maytoggle between waiting for BLE pairing, waiting for NFC and attemptingto download, or waiting for NFC and attempting to download, depending onthe communication status between the smartphone and the orthodonticappliance with the sensor (e.g., ECI). A communications manager (e.g.,the software/firmware on the smartphone) can be responsible for managingBLE or NFC only communications. It can post events so that externalcomponents or managers can act on them (e.g., a Data Manager can act ona “Data Downloaded” event, and another component, not illustrated here,could act on a “Data Uploaded” event). Similarly, FIG. 46 illustrates anexample of a process chart for a data processing component/manager.

The present disclosure provides improved systems, methods, and apparatusfor monitoring physiological characteristics of a patient's intraoralcavity and airway. Appliances are provided with sensors configured tosend, and receive signals, and a processor records those signals tomemory. The signals can be analyzed to determine physiologicalcharacteristics of the patient. The intraoral appliance may also be atreatment appliance, treating an underlying condition and monitoringphysiological characteristics to track the efficacy of that treatment.

As used herein the term “and/or” is used as a functional word toindicate that two words or expressions are to be taken together orindividually. For example, A and/or B encompasses A alone, B alone, andA and B together.

The present disclosure provides orthodontic systems, apparatus, andrelated methods for monitoring physiological characteristics of apatient, as well as for assessing treatment parameters such as applianceefficacy.

In one aspect, a method for monitoring a physiological characteristic ofa patient is provided. The method comprises positioning an intraoralappliance in the patient's intraoral cavity. The intraoral appliance isshaped to receive the patient's teeth and comprises a plurality ofelectrodes each positioned to make electrical contact with a differentpart of the patient's intraoral cavity. The method further comprisesmeasuring an electrical impedance using the plurality of electrodes anddetermining the physiological characteristic based on the electricalimpedance. In some embodiments, the measuring and determining steps areperformed by one or more processors disposed on or within the intraoralappliance.

In some cases, the physiological characteristic comprises one or moreof: airway diameter, airway volume, airway resistance, lung fluid level,soft tissue crowding, breathing rate, muscle activity, ionic compositionof saliva, or ionic composition of oral mucosa. The physiologicalcharacteristic can be related to a sleep disorder of the patient, andthe sleep disorder can comprise one or more of sleep apnea, snoring, orbruxism. In some embodiments, the sleep disorder comprises sleep apneaand the intraoral appliance is configured to treat the sleep apnea.

In some cases, the efficacy of the intraoral appliance in treating thesleep apnea is determined based on the determined physiologicalcharacteristic. The one or more processors may be configured to makethis determination.

In some cases, the electrical impedance comprises a near-field impedanceand the physiological characteristic comprises one or more of softtissue crowding, ionic composition of saliva, or ionic composition oforal mucosa. In some cases, the electrical impedance comprises afar-field impedance and the physiological characteristic comprises oneor more of lung fluid level or airway length.

In another aspect, a method is provided for monitoring a characteristicof a patient's intraoral cavity or airway. The method comprisespositioning an intraoral appliance in the patient's intraoral cavity.The intraoral appliance is shaped to receive the patient's teeth andincludes a transmitter and a receiver. The method further comprisescausing the transmitter to emit a signal within the patient's intraoralcavity, measuring a signal returning from the patient's intraoral cavityor airway in response to the emitted signal using the receiver, anddetermining the characteristic of the patient's intraoral cavity orairway based on the measured signal. In some embodiments, the measuringand determining steps are performed by one or more processors disposedon or within the intraoral appliance.

Although reference is made to an appliance comprising a polymeric shellappliance, the embodiments disclosed herein are well suited for use withmany appliances that receive teeth, for example appliances without oneor more of polymers or shells. The appliance can be fabricated with oneor more of many materials such as metal, glass, reinforced fibers,carbon fiber, composites, reinforced composites, aluminum, biologicalmaterials, and combinations thereof for example. The appliance can beshaped in many ways, such as with thermoforming or direct fabrication(e.g., 3D printing, additive manufacturing), for example. Alternativelyor in combination, the appliance can be fabricated with machining suchas an appliance fabricated from a block of material with computernumeric control machining.

FIG. 1 illustrates an impedance model of a patient's airway 4700. Theairway 4700 comprises an intraoral cavity bounded on the maxillary sideby the hard palate 101 and soft palate 4702, bounded on the mandibularside by the tongue 4703 and maxilla, and bounded on the lateral sides bythe cheeks. As the patient breathes, airflow 4704 passes through themouth and sinuses and travels down the upper airway 4705 toward thelungs. Obstruction of these passageways can cause sleep apnea, and maybe due to conditions such as soft tissue crowding or narrowing of partsof the upper airway, for example. A patient's airway may be modeled as asubstantially cylindrical passageway between the intraoral cavity andthe lungs. In some embodiments, the patient's trachea is approximated asa cylinder 4710 of length L with an outer shell 4712 of soft tissue anda hollow core 4714 filled with air. The conductivity of soft tissue ismuch higher than that of air; accordingly, the impedance of the airwaycan be approximated as the resistance of a hollow cylinder with outerradius R (the radius of the tissue surrounding the airway in the neck),inner radius r (the airway radius), and length L (the airway length).The resistivity p can be approximated as that of the airway tissue, andthe impedance 4720 can be estimated by the equation Z=μL/A, where A isthe total conductive area—in this case the outer cylinder area minus theinner (substantially non-conductive) cylinder area. This gives a totalimpedance 4720 of about Z=μL/π(R{circumflex over ( )}2-r{circumflex over( )}2). More generally, in some embodiments the impedance will beproportional to the resistivity of soft tissue and the length of theairway, while being inversely proportional to the cross-sectional areaof the conductive tissue of the airway. For electrical signals travelingbetween the intraoral cavity and the lower airway, the upper airway maythus be treated as a circuit element characterized by an impedance Zsimilar to this equation. The impedance Z depends on the inner radiusr—in particular, as r increases, Z increases, and as r decreases, Zdecreases. Thus, by measuring the variation of impedance over time, itis possible to determine changes in airway width from correspondingchanges in impedance.

Variation of airway width can be particularly important in patients withsleep apnea and related disorders, as sleep disturbance and snoring canresult from an insufficiently wide airway. FIG. 48A illustrates thevariation of patient airway width for different Mallampati scores. Apatient with a Mallampati score of I has a large, unobstructed airwaywith hard palate 201, soft palate 202, uvula 203, and pillars 204visible; a patient with a Mallampati score of II has a smaller airwaywith pillars no longer visible; a patient with a Mallampati score of IIIhas only the hard and soft palate and base of the uvula visible; and apatient with a Mallampati score of IV has only the hard palate visible.Higher Mallampati score may be associated with greater likelihood ofsleep apnea, with class III and class IV especially likely to exhibitsleep apnea.

As can be seen from FIG. 48A, in some embodiments, the unobstructedcross-sectional area of the patient's airway decreases with increasingMallampati score, such that a higher Mallampati score is associated withsmaller airway area. As discussed with respect to FIG. 1, smaller airwaycross section may correspond to lower electrical impedance. FIG. 48Billustrates the correlation between Mallampati score and airwayimpedance, plotting Mallampati score against inverse impedance 1/Z.Because increasing 1/Z corresponds to increasing Mallampati score, ameasurement of electrical impedance along the airway can be used todetermine Mallampati score. An appliance capable of measuring impedancein continuously or continually when worn by a patient allows forcontinuous monitoring of airway width, for example while a patient issleeping. Data generated by such measurements can be used in thediagnosis and treatment of sleep apnea.

In some embodiments, the present disclosure provides systems, methods,and devices for measuring characteristics of the patient's intraoralcavity and/or airway based on electrical impedance. Examples ofcharacteristics that may be measured include airway diameter, airwayvolume, airway resistance, lung fluid level, soft tissue crowding,breathing rate, muscle activity, the ionic composition of saliva, or theionic composition of oral mucosa. Measurements can be made based on nearfield impedance, far field impedance, or combinations thereof. As usedherein, near field may refer to measurements of impedance along oraround the shortest path between two electrodes. For electrodes withinthe mouth, for example, a near field impedance may be that portion ofthe impedance that depends on the resistivity and shape of the tissuesof the mouth, or a portion thereof. Near field may be used to measurecharacteristics such as muscle activity, the ionic composition ofsaliva, or the ionic composition of oral mucosa, for example. As usedherein far field may refer to impedance measurements depending on thecharacteristics away from the shortest path between two electrodes. Forelectrodes within the mouth, for example, a far field impedancemeasurement may measure the effects on impedance due to changes in shapeor resistivity of tissues in the upper or lower airway, or in the lungs.Far field may be used to measure characteristics such as airwaydiameter, airway volume, airway resistance, lung fluid level, softtissue crowding, breathing rate, for example. Impedance may be measuredbetween two or more points in the patient's intraoral cavity. Thelocation of the measurement points in the intraoral cavity may be variedas desired. For example electrodes may be placed on opposite sides ofmouth, at points on the upper and lower jaws, at points on the same jaw(upper or lower), or contacting tissues such as cheeks, palate, gingiva,teeth. The electrodes may be configured to contact points in the mouthat a separation of about 1 mm, 2 mm, 4 mm, 10 mm, 20 mm 40 mm, 100 mm,or 200 mm, for example. Shorter separations may be more sensitive tonear-field measurements, while longer separations may be more sensitiveto far-field measurements, for example.

FIG. 49A illustrates a patient's intraoral cavity 4900 in conjunctionwith points from which sensors such as electrodes can be placed tomeasure characteristics of the intraoral cavity and airway. A pair ofcontact points 4910 and 4920 are located in the intraoral cavity 4900.One contact point is located along the gingiva of the upper arch 4912,on the lingual side. Although illustrated on the right lingual side nearthe back of the mouth in FIG. 49A, the location of contact point 4910may be varied; for example, in some embodiments contact point 4910 is onthe buccal side of the upper arch, or on the left side of the mouth, orat any point along the upper or lower arch, including optionally on thesame arch as contact point 4920. Contact point 4910 may also be at apoint along a cheek of the patient. Similarly, although contact point4920 is illustrated along the gingiva of the lower arch 4922, on thebuccal side opposite the tongue 4924, the contact point 4920 may also bevaried in the same manner as contact point 4910, such that any validcontact point for one may be the contact point for the other, includingwithout limitation contact points on the lingual and/or buccal sides ofone or more arches, along the hard palate, along the cheek of thepatient, or at any other point within the mouth. The position of eachcontact point pair affects the sensitivities of measurements performedwith that pair of points.

For example, referring to the specific choice of contact pointsillustrated in FIG. 49A, because the airway of the patient stretchesaway from the intraoral cavity, the airway passageway may besubstantially in the far field with respect to electrical impedance.Accordingly, in some embodiments, it is preferred to keep near fieldsignal as small as reasonably possible so as to maximize the relativesize of far-field signal. Thus, in some embodiments points 4910 and 4920are preferably located far apart in the intraoral cavity, as well asnear the back of the mouth; in FIG. 49A, this is illustrated with point4910 located near the upper molars on one side of the mouth while point4920 is located near the lower molars on the other side of the mouth.

Electrical currents can be induced to flow between contact points, suchas points 4910 and 4920 by applying an appropriate voltage, and thesecurrents can be measured to determine electrical impedance. The voltagemay be an alternating voltage to induce an alternating current, forexample. Current pulses comprising many frequencies may be induced toallow the measurement of impedance at each of multiple differentfrequencies simultaneously and/or sequentially. In some embodiments,although a portion of the electrical impedance between contact pointssuch as points 4910 and 4920 is due to near field impedance, a portionmay also be due to far field impedance, including airway impedance.Contact points that are farther apart may tend to be more sensitive tothe far field relative to the near field, while points that are closertogether may be more sensitive to the near field relative to the farfield. This principle may also be applied for measurements performedwith sensors other than electrodes, such as transmitter-receiver pairsas disclosed herein: close-by transmitter-receiver pairs may be moresensitive to the near field while separated transmitter-receiver pairsmay be more sensitive to the far field.

Measurements such as impedance measurements can be filtered to isolatethat portion of the measured quantity and variation thereof that is dueto the variable to be measured and variation thereof. For example,current pulses may be induced and thereafter received by applying avoltage pulse between points 4910 and 4920, then later measuring areturn signal. The signal may be tracked as a function of time. The timeit takes for a pulse to travel to the lungs and back can correspond tothe round trip distance divided by the speed of electrical current,which can be a significant fraction of the speed of light. Withsufficient time resolution, such as nanosecond resolution, it ispossible to determine how far a pulse has traveled based on its roundtrip time; by measuring signal strength at the delay time correspondingto a round trip through the airway, a direct measurement of the farfield impedance of the airway can be obtained. In some cases, therelative phase of current pulses may be measured to determine the farfield impedance, as phase can be affected by time delay.

A portion of the near-field impedance will also depend on the airwaywidth, as the available paths between points 4910 and 4920 along thesurface of the intraoral cavity include paths that travel near theairway opening. If the airway opening is smaller, shorter paths areavailable, which lowers impedance in the near field. Impedance can alsobe measured repeatedly over longer time periods to allow betterfiltering of noise sources and isolation of the effect of airway widthvariation on impedance. For example, as a patient breathes the airwaychanges shape, so variations in airway impedance correlated with patientrespiration can be used to isolate impedance variation caused by airwaywidth variation. Similarly, for other measurements, changes in impedanceor other measured properties can be correlated to that particularmeasurement; for example, changes in ionic saliva content can bedetermined from near field impedance changes, and physical properties ofa tooth or tooth-PDL system can be determined from measured accelerationin response to forces applied by an actuator. It will be appreciatedthat points 4910 and 4920 may be varied throughout the intraoral cavityto change the measurement sensitivity and specificity; for example, todetermine appropriate positions for measurement sensor location, aplurality of point pairs can be tested in the mouth of a patient, andthe point pair with highest signal-to-noise ratio for that measurementcan be selected for use in that patient or other patients. Othermeasurements, such as transmitter-receiver measurements, may follow thesame pattern for their respective measurement variables and can likewisebe placed at variable positions throughout the intraoral cavity tochange their sensitivities and specificities for their respectivemeasurements.

FIG. 49B illustrates alternative positions in which sensors such aselectrodes can be placed to measure characteristics of the intraoralcavity and airway. In sensor configuration 350, a first sensor 360 islocated along the maxillary palate near the soft tissue 362 and uvula364. A second sensor is located along the mandibular palate between thetongue 374 and the mandibular teeth (not shown). In this embodiment, thesensors are located on opposite sides of the airway, such that theairway lies along the shortest path between the two sensors. In the casethat sensors 360 and 370 are electrodes, for example, the impedancebetween the two sensors will depend in part on the width of the airway,with lower impedance corresponding to a narrower (and thus moreoccluded) airway.

In some embodiments, the impedance measurements described herein areperformed using electrical sensors coupled to an oral appliance.Examples of such oral appliances include dental retainers, aligners, andmouthguards. In some embodiments, the oral appliance is used to treatsleep apnea, such as a mandibular advancement device. In someembodiments, a mandibular advancement device is worn by the patient inthe order to displace the lower jaw anteriorly relative to the upper jawto treat sleep apnea. The mandibular advancement device can be apatient-removable appliance (e.g., the patient can place and remove theappliance without aid from a practitioner) that is inserted into thepatient's mouth prior to sleep so as to maintain the lower jaw in anadvanced position during sleep, and is removed from the patient's mouthwhile the patient is awake to allow for normal activity. In alternativeembodiments, the intraoral appliance can include one or more componentsthat are not patient-removable (e.g., attachments or brackets affixed toone or more teeth, anchoring devices positioned in the tissue of theintraoral cavity such as bone). In some embodiments, the intraoralappliance includes at least one appliance shell having a plurality ofcavities shaped to receive teeth of a single jaw of the patient.

Any number of sensors can be used, such as electrodes, acoustictransducers, and accelerometers. The sensors can be located in anyportion of the appliance, such as adjoining the lingual or buccal sidesof the gingiva, adjoining the dental surfaces of teeth, adjoining thecheeks, or along the roof or bottom of the mouth. The sensors can becoupled to the appliance in various ways, such as by adhesives,fasteners, embedding within the appliance material, or insertion intocavities formed in the appliance. The measurements described herein maybe obtained using sensors coupled to a single appliance worn on thepatient's upper or lower jaw. Alternatively, sensors may be distributedbetween a pair of appliances worn on the upper and lower jaws,respectively. In some embodiments, the oral appliance(s) and sensors arecontained entirely within the patient's intraoral cavity when worn. Forexample, in some embodiments the appliances can be operated withoutconnection to external power sources, control electronics, or externalsensor points. The appliance electronics can comprise a power sourcesuch as a battery to store energy for continuous operation. The batterycan be rechargeable, for example, by plugging the appliance into arecharger when not in use or by recharging using wireless powertransfer—in the latter case the appliance can comprise appropriateantenna(s) to receive transmitted power from a base station. The oralappliance(s) and sensors may be patient-removable, allowing formeasurements to be performed without the need for sensor apparatus beingimplanted within patient tissue or affixed to the mouth or teeth of thepatient.

FIGS. 50A-50G illustrate a variety of oral appliances comprisingelectrical sensors such as electrodes positioned in variousconfigurations to allow measurement of impedance due to airway widthvariation, as well as other physiological characteristics of a patient,including characteristics of a patient's intraoral cavity or airway.Electrodes can be used to monitor resistance changes within the oralcavity, as in patients with abnormal soft tissue crowding, theconductive paths between electrodes may be shorter. Because stretchingof soft tissue during changes in mandibular position can alter theconductive pathways within the intraoral cavity, impedance measurementscan be used to detect whether the patient has an open or closed mouth,for example, or whether the mandible is retruded or protruded. Whilewell-separated electrodes may be desirable for increased sensitivity tofar-field impedance variation in some embodiments, closely-positionedelectrodes can also be used for monitoring of physiologicalcharacteristics of the patient. For example, the electrical potentialgenerated by muscle cells during activation may be monitored byappropriately-positioned electrodes. Among the physiological activitiesthat may be detected by monitoring muscle movements in this way aretemporomandibular joint articulation, increased masseter activity duringparafunctional activity (such as grinding or clenching), and upperairway relaxation due, for example, to upper airway collapse or decreasein activity, which are associated with hypopnea or apnea.

Although electrodes are used herein as exemplary sensors in theillustrated orthodontic appliances, sensors other than electrodes may beused for sensing physiological properties of a patient's intraoralcavity and/or airway, by measuring properties other than impedance, suchas piezoelectric pulses, acoustic waves, and acceleration. In someembodiments, the physiological properties can be measured bytransmitting a signal into the patient's intraoral cavity and/or airway,and measuring the response signal returning from the intraoral cavityand/or airway. The characteristics of the response signal (e.g.,amplitude, frequency, etc.) may vary based on the properties of thepatient's intraoral cavity and/or airway.

In such embodiments, the electrodes marked in FIGS. 50A-50G may bereplaced with appropriate pairs of sensors, acting as transmitter andreceiver respectively. For example, transducers can be used forgenerating and receiving acoustic waves (e.g., ultrasound), and phaseand magnitude information of the response signal can be used to imagethe oral cavity or upper airway. An actuator (such as a piston,vibration motor, or piezo-electric crystal) and an accelerometer mayreplace respective electrodes. An impulse signal can be sent to a toothvia the actuator and a response signal can be recorded with anaccelerometer in contact with the tooth. This response can be correlatedwith different phases of tooth movement, such as movement due toorthodontic forces applied by an appliance shell, because the stiffnessof the tooth-PDL structure will vary with different stages of toothmovement. The response may also be correlated with tooth, root, and/orPDL health, even if no tooth movement is being induced by the applianceshell. Actuators may also be placed to produce forces that can result inelectrical currents (for example, via the piezoelectric effect) instructures of the mouth. For example, compression of bone and collagenresults in movement of electrons in the crystal lattice, and applicationof force on the teeth can result in a short piezoelectric effect on thealveolar bone which may be detected by appropriate receiving sensorssuch as electrodes. Electrical signals produced by alveolar andperiodontal ligaments (PDL) when under load can stimulate changes inbone metabolism—electrical sensors such as electrodes may also be usedto detect these electrical signals, for example, by monitoring changesin voltage. These examples of measurements can be combined to performsimultaneous or staggered measurements, including combinations withelectrode measurements of impedance and other electrical properties. Insome embodiments, multiple measurements are performed and their resultscompared or combined using sensor fusion techniques, thereby improvingresolution of each measured quantity.

FIG. 50A illustrates an appliance 5000 wearable over a patient's teethcomprising sensors positioned at diametrically opposed points in apatient's intraoral cavity 5002. The appliance 5000 comprises a shell5004 with teeth-receiving cavities configured to receive the teeth of apatient when worn in the patient's mouth 5002. The appliance shellcomprises protruding portions 405 configured to extend along the cheeksof the patient when the appliance is worn. The protruding portions canbe configured to engage protruding portions of an appliance worn on theopposite jaw to provide forces for mandibular advancement, for example.The appliance further comprises a plurality of sensors such aselectrodes, with a first electrode 5006 disposed on a protrusion andpositioned to come into contact with the right cheek of the patient whenworn. The second electrode 5008 is disposed on the shell and positionedto come into contact with the left cheek of the patient when worn. Theillustration of the patient's intraoral cavity 5002 shows the pointswhich are contacted by each electrode when the appliance is worn. Theelectrodes are positioned to contact substantially opposite points nearthe rear part of the patient's intraoral cavity, providing electricalcontact points in areas similar to those illustrated in FIG. 49A. As aresult, the electrode positions are well-suited to measure far-fieldimpedance, for example. In alternative embodiments, the appliance 5000can also be used to perform other types of measurements, as discussedherein.

The appliance 5000 further comprises appropriate wiring disposed withinshell 5004, providing electrical contact between sensors, illustrated aselectrodes 5006 and 5008 and a processor disposed within the shell. Theprocessor is further connected to a power source such as a battery thatprovides electrical power. The processor is configured to controlvoltage values at each electrode to allow the generation of currentpulses, alternating current, and/or direct current flow. The circuitryconnecting the processor to the electrodes further comprises a currentmeasuring unit, such as an ammeter, so that impedance may be calculatedby the processor by a measurement of voltage and current as a functionof time. The processor comprises a clock for time measurement, and isconnected to memory to allow the recording of sensor data, as well as tocontain instructions to be executed by the processor. Optionally, theprocessor is further connected to a wireless radio transmitter, allowingrecorded data to be transmitted to an external receiver for processingby an external computing device. The external receiver may be, forexample, a mobile device or WiFi antenna, and the receiver andtransmitter may communicate using an appropriate communications protocolsuch as Bluetooth, cellular, WiFi, or other protocols. FIG. 50C providesmore detail of the internal structure of an appliance such as thatillustrated in FIG. 50A.

FIG. 50B illustrates an appliance 5010 wearable over a patient's teeth5012 comprising sensors positioned close proximity to each other. Theappliance comprises an appliance shell 5014 and the sensors comprise aplurality of electrodes 5016 in close proximity to each other. Sensorssuch as electrodes may be in close proximity when, for example, theshortest distance between them is small compared to the width of theairway. Sensors in close proximity may be more sensitive to near-fieldmeasurements then more distantly-separated sensors. The electrodes areconfigured to contact a plurality of nearby points 5018 within thepatient's intraoral cavity when the appliance is worn by the patient. Inthis illustration, the contact points are located on the buccal gingiva;in other embodiments, the contact points may be on the cheeks or lips,or on the lingual side touching the tongue and lingual gingiva. Thecontact points may also touch the teeth on the lingual and/or buccalside (including one sensor on each side of a tooth). The nearbyelectrodes are sensitive to near-field variations in impedance;accordingly, they may be used to measure properties such as intraoralimpedance caused by changes in saliva quantity or contents. For example,if a patient's mouth becomes more dry, the amount of saliva betweenelectrodes 5016 and around points 5018 will diminish, which can increasethe impedance as saliva is not available to carry electrical current.Similarly, changes in contents of saliva, such as pH shifts, can bemeasured, for example, by their resultant changes in salivaconductivity. These properties may also be measured in combination withfar field measurements by providing an appliance with both near-fieldand far-field electrode configurations, such as by adding near-fieldelectrodes such as illustrated in FIG. 50B to an appliance withfar-field electrodes such as FIG. 50A. The respective electrode pairscan be separately connected to and controlled by the processor, or maybe controlled by separate processors.

FIG. 50C illustrates an interior of an appliance 430 with an embeddedmeasurement system comprising control electronics and sensors. Theappliance 430 comprises oral appliance layers 431 and 432, whichsurround control electronics 433. Control electronics 433 include apower source such as a battery, drive electronics to generate electricalvoltage pulses for inducing electrical current, and measurementelectronics for measuring electrical current and voltage as a functionof time, then recording the resulting data to memory. The controlelectronics 433 comprise a processor and memory, the memory containinginstructions that, when executed, cause the processor to control thedrive and measurement electronics to produce electrical pulses andperform measurements such as impedance measurements, according to themethods as disclosed herein. The control electronics are electricallycoupled with wires 434 to one or more sensors such as electrodes 436 and438. The wires 434 are preferably disposed within the layers of theappliance shell, but may include open connections between shells (seeFIG. 50E, for example). The electrodes are disposed to contact thesurfaces of the patient's intraoral cavity when the appliance is worn.The electrodes perform both current generation and electricalmeasurement, under the direction of the control electronics. The basicschematic layout shown in FIG. 50C may be used, with appropriatevariations in positions of electrodes, driver electronics, andmeasurement electronics, in any of a variety of appliance shellconfigurations, including configurations as shown in FIGS. 50A, 50B, and50D-50G.

FIG. 50D illustrates examples of alternative, extended positions forsensors such as electrodes and drive electronics. The configurations ofappliance shells and electrodes as shown in FIGS. 50A, 50B, and 50E-50Gmay be varied to place drive and measurement electronics and electrodesin alternative positions, as needed. For example, FIG. 50D illustratesan appliance 440 with certain variations of this type. The driveelectronics 441 of appliance 440 are located outside of the shell,allowing an extra-oral measurement device to be connected. For example,the lead wires 442 may be connected to an external device while thepatient sleeps, allowing the appliance to record impedance and otherdata without needing an internal power source. Electrodes may be locatedin a tab 443 extending from the gingival edge of the appliance, or evenin a flexible, wired connection, such as electrode 444. Electrode 444can be attached to an appliance or dental attachment on the oppositeside of the patient's mouth as appliance 440, for example. This allows agreater flexibility in electrode configuration for performing a varietyof measurements within the intraoral cavity of the patient. The tab 443may be a preloaded tab with an electrode on an inner surface to allowcontact to be maintained. As shown in the cross-section view 445 of aportion of appliance 440, the tab 443 is configured to elastically bendbetween a first configuration 446 away from the dentition and gums and asecond configuration 447 pressing an electrode against the gums of thepatient when the appliance is worn. The tab 443 is configured to apply apreloaded inwards force to keep the tab in the second configuration 447to maintain electrical contact between the electrode and the gums of thepatient. Such an electrode position is useful, for example, inmeasurements of impedance and other electrical characteristics of theperiodontal ligaments (PDL).

FIG. 50E illustrates an appliance comprising an upper shell to fit apatient's upper teeth and a lower shell to fit the patient's lowerteeth, each shell comprising an sensor such as an electrode. Theappliance 450 comprises an upper shell 451 comprising an upper electrode453, and a lower shell 452 comprising a lower electrode 454. Eachelectrode is located on a protrusion of a mandibular advancement devicefor the treatment of a condition such as OSA, and the protrusions areconfigured to come into contact when each appliance is worn on thepatient's respective upper and lower teeth to advance the mandible, forexample. The interface 455 between protrusions can comprise conductivesurfaces on each protrusion, such that the protrusions form anelectrical contact, allowing each electrode to be controlled by aprocessor in one of the two shells. It will be understood that theelectrodes 453 and 454 do not have to be located on the protrusions, butmay instead be located elsewhere on their respective shells (forexample, on opposite sides of the patient's mouth). In such a case,wires may be provided within the shells to connect the electrodes, theprocessor, and the interface 455 together.

FIG. 50F illustrates an appliance configured to measure physiologicalproperties using electrodes on opposite sides of the appliance shell.The appliance 460 comprises an appliance shell 462 with two electrodes464 and 466 on opposite sides of the shell. An impedance 468 may bemeasured between the electrodes, as illustrated in FIG. 50F in the formof a partial circuit diagram. The appliance shell 462 comprises controlelectronics including a processor and memory, for example as illustratedin FIG. 50C. The processor determines the impedance Z betweenelectrodes, which is then used to determine one or more physiologicalcharacteristics of the patient; for example, airway cross-sectionalarea.

FIG. 50G illustrates an appliance 470 with respective sensors on upperand lower shells, in which the electronic systems of the sensors areinductively coupled. The appliance 470 comprises an upper shell 471 witha sensor 472 and a lower shell 472 with a sensor 474. The two shellseach comprise respective control electronics including respectiveprocessors, power sources, and measurement and drive electronics. Thetwo shells are not configured to form direct electrical contact;instead, the electronics of the upper and lower shells are inductivelycoupled, such that each responds to transient electrical pulses emittedfrom the other. The sensors of FIG. 50G can be configured with onesensor being a transmitter and one being a receiver; for example, anacoustic transmitter and receiver may be used. In this manner,measurements may be performed relating signals to and from sensors ineach respective shell without requiring an electrical pathway connectingthe upper and lower shell electronics.

In cases in which sensors are located on separate upper and lowerappliance shells the two shells may be coupled in various ways to enablecoordinated measurement. For example, conductive coupling can beachieved in various ways. A wired connection can be made betweenopposing arches. In some embodiments, a single, monolithic appliance maybe more practical than an appliance for both arches. However, whereintermittent sensing is acceptable, conductive connectors can be placedon known contact points, such as is illustrated in FIG. 50E. In anotherexample of coupling, a conductive articulating rod such as aHerbst-style rod can be included between shells to provide a conductivepath. Other methods of coupling directly include stretchable conductors,which can function like orthodontic elastics between appropriate hooksor buttons, or implanted wires within the mouth of the patient, such assubcutaneous wires in the cheek or adhesive wires attached on the innersurface of the intraoral cavity.

FIG. 51A illustrates a block diagram of a signal chain 5100 forperforming impedance measurements with the appliances disclosed herein.The driver electronics provide a current 5110 to an electrodecharacterized by a carrier frequency Fc. To eliminate DC current, thecurrent transmitting electrode is screened from the current source by ahigh-pass filter in the form of a capacitor 5120. The electrode contactsthe patient's intraoral cavity, which provides modulation 530 at lowfrequencies, corresponding to variations in electrical impedance. Thisimpedance can be modeled as a baseline impedance RB plus a variableimpedance ΔR. The modulation is due to changes in ΔR, for example,arising from changes in airway cross-sectional area as the patientbreathes. The modulated signal is received at the receiving electrode,which is also screened by a high-pass filter in the form of a capacitor540. The received signal is then amplified by a gain stage 550.Thereafter, the signal is synchronously demodulated 560 to remove thecarrier frequency Fc. Remaining high-frequency components are removedwith a low-pass filter 570, producing the final signal to be measured.An analog-to-digital converter 580 then converts the signal to a digitalsignal, which is processed by a processor that records the resultingmeasurement data to a non-transitory computer-readable medium.

When the signal chain disclosed in FIG. 51A is applied to monitorphysiological characteristics within the mouth of a patient, it isimportant to use signal frequencies and amplitudes that do not irritateor harm the patient. For inductive measurements with electrodes, saferanges for current may be about 100 μA or less. Carrier frequencies usedto modulate the signals can be chosen to appropriately minimize noise;for example, a carrier frequency of about 10 kHz is useful for manyapplications. The signal chain disclosed in FIG. 51A may be applied tosystems using sensors other than electrodes, replacing the electrodesdescribed above with the appropriate sensor, such as a transducer, apiezo-electric crystal, or an actuator/accelerometer pair. The impedancemodulation will correspondingly be replaced with a modulation of thesignal to which the particular sensor is sensitive. For systems applyingmechanical energy, the mechanical energy applied can be kept less thanabout 1 N for continuous force. For transient forces such as periodicforces, larger forces may be applied; for example, an amplitude of about5 N or less can be applied for transient force measurements.

FIG. 51B shows a schematic diagram of an oral appliance comprising aplurality of electrodes for measuring the impedance of a system such asthe intraoral cavity or airway of a patient. A power source 515 suppliesan alternating current to a first electrode lead 525. The electrode lead525 can be brought into contact with a system 535 to be measured, suchas the intraoral cavity of a patient. The voltage drop between lead 525and lead 545 varies based on the impedance of the system 535, in amanner approximated by Ohm's law (V=I*Z); accordingly, the relationshipbetween the voltage drop and current flow between electrodes 525 and 545can be used to determine the impedance of the system 535. Each of thevoltage and the current can be measured using conventional methods,e.g., with voltmeters and/or ammeters. A pull-up or pull-down resistor555 can be included to ensure the incoming electrical signal has anappropriate voltage reference. The incoming AC signal from electrodelead 545 is then demodulated at signal conditioner 565, with gainapplied as needed to amplify the signal. Remaining high-frequencyelements are removed with a low-pass filter, and the signal is thenrecorded to memory 575 for analysis. As data are accumulated over time,a data plot 585 of impedance vs time can be generated for analysis bythe processor. The data can also be transmitted to an external devicesuch as a mobile device for display and analysis, e.g., by a medicalprofessional.

FIG. 52 illustrates a method 5200 for monitoring a physiologicalcharacteristic of a patient using an intraoral appliance as disclosedherein.

In step 610, the appliance is positioned in the mouth of a patient. Theappliance may comprise, for example, an appliance shell, or even aplurality of appliance shells, such as those disclosed herein. Theappliance comprises a plurality of electrodes disposed within the one ormore shells, and configured to make electrical contact with thepatient's intraoral cavity when the intraoral appliance is worn by thepatient.

In step 620, an impedance measurement is performed by a processorcoupled to the electrodes. The impedance measurement may, for example,be performed using a signal chain such as signal chain 500. Thevariation of impedance due to physiological changes of the patient suchas changes in airway occlusion causes a modulation of a current signal.After amplification and demodulation of a carrier frequency of thecurrent signal, the remaining signal can be sent through a low-passfilter to retrieve an analog signal. The variation of that signalcorresponds to variation in impedance. An analog-to-digital convertercan generate signal data readable by the processor as a sequence ofsignal values over time, and the sequence contains information fromwhich impedance variation can be determined. For example, variations inimpedance due to breathing can be determined by detecting signalvariations with substantially similar frequencies to the breathing rate.

In step 630, the processor records data to memory corresponding to theimpedance measurement. Optionally, the processor may cause a transmitterto transmit the data to a remote receiver to be recorded in memoryoutside the appliance. For example, a mobile device or other computingdevice may communicate with the processor using wired or wirelesstechnology (such a Bluetooth, WiFi, or cellular communication, forexample.)

In step 640, a physiological characteristic is determined based on theimpedance measurement data recorded in memory. For example, thephysiological characteristic may be airway diameter, airway volume,airway resistance, lung fluid level, soft tissue crowding, breathingrate, muscle activity, ionic composition of saliva, or ionic compositionof oral mucosa, or a combination thereof. Airway diameter, volume, andresistance can be determined by measuring variation in far-fieldimpedance as measured by the electrodes. These size changes can be usedas indicators of soft-tissue crowding. The signal can be isolated bydetecting impedance variations correlated with patient breathing, forexample. Breathing rate may be determined by detecting slow, periodicvariations in overall impedance with time periods on the order ofseconds. Lung fluid level can be determined by measuring properties ofreturning electrical current pulses, in particular their delay time andphase. Muscle activity, ionic composition of saliva, or ioniccomposition of oral mucosa can be measured with near-field electrodes:changes in ionic composition change electrical impedance of theintervening fluid, and muscle activity generates electrical currentsthat can be detected with the electrodes.

FIG. 53 illustrates a method 5300 for monitoring a characteristic of apatient's intraoral cavity or airway using transmitter-receiver pairsdisposed within an intraoral appliance.

In step 5310, the appliance is positioned in the mouth of a patient. Theappliance may comprise, for example, an appliance shell, or even aplurality of appliance shells, such as those disclosed herein. Theappliance comprises a transmitter and a receiver disposed within the oneor more shells. For example, the transmitter and the receiver may bepositioned in place of the electrodes in appliances substantially asdescribed in FIGS. 50A-50F. The transmitter and receiver may also bedisposed in a pair of shells with inductively coupled electronics, asdisclosed in FIG. 50G.

In step 5320, the transmitter transmits a signal within the intraoralcavity. Examples of transmitters and respective transmitted signalsinclude an electrode transmitting electrical pulses, a transducertransmitting acoustic waves, and an actuator transmitting mechanicalforce.

In step 5330, a response signal is received and processed by aprocessor, then recorded to memory. The response signal can arise froman interaction between the transmitted signal and portions of thepatient's intraoral cavity and/or airway, such as a scattering,reflection, or stimulation of tissue or fluids, for example. Theresponse signal is received by a receiving sensor. Examples of receivingsensors and respective received signals include an electrode receivingpiezoelectric pulses, a transducer receiving reflected acoustic waves,and an accelerometer detecting acceleration. The received signalcontains information about the tissues and/or fluids it traveled throughthat can be analyzed to determine physiological characteristics; forexample, modulations of the amplitude, frequency and phase of thereceived signals can correspond to corresponding changes in thetransmission medium of the patient's intraoral cavity or airway.

In step 5340, a physiological characteristic is determined based on thesensor measurement data recorded in memory. The determined physiologicalcharacteristic can be, for example, compression response of bone andcollagen; temporomandibular joint articulation; grinding or clenching ofteeth; decline in upper airway muscle activity; stiffness of tooth-PDLstructure; tooth, root, and/or PDL health; root structures based onacoustic responses of surrounding tissue; oral cavity or upper airwayshape and size; soft tissue crowding; opening or closing of the mouth;or mandibular protrusion or retrusion. These physiologicalcharacteristics may be respectively determined using the appropriatesensors and physiological relationships as described above regardingFIGS. 50A-50G.

FIG. 54 illustrates a method of manufacturing an appliance comprisingsensors and control electronics 5400.

In step 5410, the dental structure of the patient is obtained. Thisstructure may be in the form of a physical mold or model, for example,or a 3D image of the patient's dentition.

In step 5420, a first layer of appliance material is deposited. Thisdeposition may be, for example, the application of a thermoformed layerof plastic over a mold. Alternatively, material may be deposited bydirect fabrication, such as using a 3D printer, according to a 3D modelof the appliance generated to fit the teeth of the patient, based on the3D image of the patient's dentition in step 5410. In some embodiments,steps 5420 and 5440 can be combined into a single step in which theappliance shell is directly fabricated around the control electronicsand sensors of step 5430.

In step 5430, control electronics and sensors are placed over the firstlayer of appliance in appropriate locations. Wiring is provided asneeded to connect each component of the sensing system. In this step,carbon fiber can be incorporated into the aligner to create an antennafor wireless communication to an external receiver. Multiple electrodesor other sensors can be provided to enhance signal acquisition; forexample, in a manner similar to neuroelectrodes used forelectroencephalogram measurements.

In step 5440, a second layer of appliance material is deposited, as instep 5420. The second layer, in combination with the first layer,envelops the control electronics and sensors.

In step 5450, any material covering sensor leads can be removed, ifnecessary. For example, a robotic mill or laser cutter may be used toremove appliance material covering electrodes, transducers, actuators,accelerometers, etc., so as to provide a clear contact with theappropriate part of the patient's mouth when the appliance is worn.

In order to better isolate signals relevant to the physiologicalcharacteristics to be measured, multiple sensor systems can be combinedusing a sensor fusion technique. For example, as discussed above, airwaywidth variation is correlated with patient breathing. Patient breathingrate can be determined using an accelerometer disposed within theintraoral appliance. FIG. 55 illustrates exemplary rotational velocitydata collected with a gyroscopic accelerometer coupled to the maxilla ofa patient. The grey spectra illustrate rotational velocity data a sensorloosely coupled to the body, near the hip. The black spectra illustratecorresponding data from a sensor coupled to the jaw of the patient viaan appliance. The left spectra illustrate the raw data in each of the x,y, and z dimensions, while the right spectra illustrate the same datatransformed into Fourier space and displayed as a power spectrum. Thepower spectrum of the black curve, measuring jaw movement, shows amaximum somewhat below 1 Hz, corresponding to the breathing rate of thepatient. By contrast, the measurement at the patient's hip shows only aweak signal. Thus, intraoral measurement can be used to measure a signalsensitive to a patient's breathing rate. Using this measured breathingrate, it is possible to isolate the effect of airway width variation onimpedance measurements from electrodes by detecting impedance variationswith substantially matching frequencies. Since impedance measurementsare also sensitive to the breathing of the patient, impedance andacceleration signal can be measured by an intraoral appliance andcross-validated to provide a breathing rate measurement with enhancedaccuracy.

In some embodiments, an appliance comprising sensors as disclosed hereincan be a treatment appliance, such as an orthodontic appliance or anappliance for the treatment of sleep apnea. In such an appliance, themonitoring of physiological conditions can comprise an assessment oftreatment efficacy. For example, sleep apnea can be treated with theintraoral appliance, and the effectiveness can be monitored by trackingthe resulting change in airway diameter or volume. The movement of teethdue to orthodontic forces can also be measured, such as by monitoringthe stiffness of a tooth-PDL structure to which orthodontic forces arebeing applied by the appliance.

Appliances having teeth receiving cavities such as those disclosedherein include appliances that receive and reposition teeth, e.g., viaapplication of force due to appliance resiliency. Examples of suchappliances are generally illustrated with regard to FIG. 1A. FIG. 1Aillustrates an exemplary tooth repositioning appliance or aligner 1000that can be worn by a patient in order to achieve an incrementalrepositioning of individual teeth 1002 in the jaw. The appliance caninclude a shell having teeth-receiving cavities that receive andresiliently reposition the teeth. An appliance or portion(s) thereof maybe indirectly fabricated using a physical model of teeth. For example,an appliance (e.g., polymeric appliance) can be formed using a physicalmodel of teeth and a sheet of suitable layers of polymeric material. Insome embodiments, a physical appliance is directly fabricated, e.g.,using rapid prototyping fabrication techniques, from a digital model ofan appliance.

Although reference is made to an appliance comprising a polymeric shellappliance, the embodiments disclosed herein are well suited for use withmany appliances that receive teeth, for example appliances without oneor more of polymers or shells. The appliance can be fabricated with oneor more of many materials such as metal, glass, reinforced fibers,carbon fiber, composites, reinforced composites, aluminum, biologicalmaterials, and combinations thereof for example. The appliance can beshaped in many ways, such as with thermoforming or direct fabrication(e.g., 3D printing, additive manufacturing), for example. Alternativelyor in combination, the appliance can be fabricated with machining suchas an appliance fabricated from a block of material with computernumeric control machining.

An appliance can fit over all teeth present in an upper or lower jaw, orless than all of the teeth. The appliance can be designed specificallyto accommodate the teeth of the patient (e.g., the topography of thetooth-receiving cavities matches the topography of the patient's teeth),and may be fabricated based on positive or negative models of thepatient's teeth generated by impression, scanning, and the like.Alternatively, the appliance can be a generic appliance configured toreceive the teeth, but not necessarily shaped to match the topography ofthe patient's teeth. In some cases, only certain teeth received by anappliance will be repositioned by the appliance while other teeth canprovide a base or anchor region for holding the appliance in place as itapplies force against the tooth or teeth targeted for repositioning. Insome embodiments, some, most, or even all of the teeth will berepositioned at some point during treatment. Teeth that are moved canalso serve as a base or anchor for holding the appliance as it is wornby the patient. Typically, no wires or other means will be provided forholding an appliance in place over the teeth. In some cases, however, itmay be desirable or necessary to provide individual attachments or otheranchoring elements 1004 on teeth 1002 with corresponding receptacles orapertures 1006 in the appliance 1000 so that the appliance can apply aselected force on the tooth. Exemplary appliances, including thoseutilized in the Invisalign® System, are described in numerous patentsand patent applications assigned to Align Technology, Inc. including,for example, in U.S. Pat. Nos. 6,450,807, and 5,975,893, as well as onthe company's website, which is accessible on the World Wide Web (see,e.g., the url “invisalign.com”). Examples of tooth-mounted attachmentssuitable for use with orthodontic appliances are also described inpatents and patent applications assigned to Align Technology, Inc.,including, for example, U.S. Pat. Nos. 6,309,215 and 6,830,450.

FIG. 1B illustrates a tooth repositioning system 1010 including aplurality of appliances 1012, 1014, 1016. Any of the appliancesdescribed herein can be designed and/or provided as part of a set of aplurality of appliances used in a tooth repositioning system. Eachappliance may be configured so a tooth-receiving cavity has a geometrycorresponding to an intermediate or final tooth arrangement intended forthe appliance. The patient's teeth can be progressively repositionedfrom an initial tooth arrangement to a target tooth arrangement byplacing a series of incremental position adjustment appliances over thepatient's teeth. For example, the tooth repositioning system 1010 caninclude a first appliance 1012 corresponding to an initial tootharrangement, one or more intermediate appliances 1014 corresponding toone or more intermediate arrangements, and a final appliance 1016corresponding to a target arrangement. A target tooth arrangement can bea planned final tooth arrangement selected for the patient's teeth atthe end of all planned orthodontic treatment. Alternatively, a targetarrangement can be one of some intermediate arrangements for thepatient's teeth during the course of orthodontic treatment, which mayinclude various different treatment scenarios, including, but notlimited to, instances where surgery is recommended, where interproximalreduction (IPR) is appropriate, where a progress check is scheduled,where anchor placement is best, where palatal expansion is desirable,where restorative dentistry is involved (e.g., inlays, onlays, crowns,bridges, implants, veneers, and the like), etc. As such, it isunderstood that a target tooth arrangement can be any planned resultingarrangement for the patient's teeth that follows one or more incrementalrepositioning stages. Likewise, an initial tooth arrangement can be anyinitial arrangement for the patient's teeth that is followed by one ormore incremental repositioning stages.

The various embodiments of the orthodontic appliances presented hereincan be fabricated in a wide variety of ways. As an example, someembodiments of the appliances herein (or portions thereof) can beproduced using indirect fabrication techniques, such as by thermoformingover a positive or negative mold. Indirect fabrication of an orthodonticappliance can involve producing a positive or negative mold of thepatient's dentition in a target arrangement (e.g., by rapid prototyping,milling, etc.) and thermoforming one or more sheets of material over themold in order to generate an appliance shell. Alternatively or incombination, some embodiments of the appliances herein may be directlyfabricated, e.g., using rapid prototyping, stereolithography, 3Dprinting, and the like.

The configuration of the orthodontic appliances herein can be determinedaccording to a treatment plan for a patient, e.g., a treatment planinvolving successive administration of a plurality of appliances forincrementally repositioning teeth. Computer-based treatment planningand/or appliance manufacturing methods can be used in order tofacilitate the design and fabrication of appliances. For instance, oneor more of the appliance components described herein can be digitallydesigned and fabricated with the aid of computer-controlledmanufacturing devices (e.g., computer numerical control (CNC) milling,computer-controlled rapid prototyping such as 3D printing, etc.). Thecomputer-based methods presented herein can improve the accuracy,flexibility, and convenience of appliance fabrication.

In some embodiments, orthodontic appliances, such as the applianceillustrated in FIG. 1A, impart forces to the crown of a tooth and/or anattachment positioned on the tooth at one or more points of contactbetween a tooth receiving cavity of the appliance and received toothand/or attachment. The magnitude of each of these forces and/or theirdistribution on the surface of the tooth can determine the type oforthodontic tooth movement which results. Tooth movements may be in anydirection in any plane of space, and may comprise one or more ofrotation or translation along one or more axes. Types of tooth movementsinclude extrusion, intrusion, rotation, tipping, translation, and rootmovement, and combinations thereof, as discussed further herein. Toothmovement of the crown greater than the movement of the root can bereferred to as tipping. Equivalent movement of the crown and root can bereferred to as translation. Movement of the root greater than the crowncan be referred to as root movement.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising” means various components can be co-jointlyemployed in the methods and articles (e.g., compositions and apparatusesincluding device and methods). For example, the term “comprising” willbe understood to imply the inclusion of any stated elements or steps butnot the exclusion of any other elements or steps.

In general, any of the apparatuses and methods described herein shouldbe understood to be inclusive, but all or a sub-set of the componentsand/or steps may alternatively be exclusive, and may be expressed as“consisting of” or alternatively “consisting essentially of” the variouscomponents, steps, sub-components or sub-steps.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical valuesgiven herein should also be understood to include about or approximatelythat value, unless the context indicates otherwise. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. Anynumerical range recited herein is intended to include all sub-rangessubsumed therein. It is also understood that when a value is disclosedthat “less than or equal to” the value, “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “X” is disclosed the “less than or equal to X” as well as “greaterthan or equal to X” (e.g., where X is a numerical value) is alsodisclosed. It is also understood that the throughout the application,data is provided in a number of different formats, and that this data,represents endpoints and starting points, and ranges for any combinationof the data points. For example, if a particular data point “10” and aparticular data point “15” are disclosed, it is understood that greaterthan, greater than or equal to, less than, less than or equal to, andequal to 10 and 15 are considered disclosed as well as between 10 and15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11,12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

What is claimed is:
 1. An apparatus for monitoring a physiologicalcharacteristic of a patient, the apparatus comprising: an intraoralappliance shaped to receive the patient's teeth and comprising aplurality of electrodes each positioned to make electrical contact withthe patient's intraoral cavity when the intraoral appliance is worn bythe patient; and one or more processors configured to: measure anelectrical impedance using the plurality of electrodes, and determinethe physiological characteristic based on the electrical impedance. 2.The apparatus of claim 1, wherein the physiological characteristiccomprises one or more of: airway diameter, airway volume, airwayresistance, lung fluid level, soft tissue crowding, breathing rate,muscle activity, ionic composition of saliva, or ionic composition oforal mucosa.
 3. The apparatus of claim 1, wherein the physiologicalcharacteristic is related to a sleep disorder of the patient, the sleepdisorder comprising one or more of sleep apnea, snoring, or bruxism. 4.The apparatus of claim 3, wherein the sleep disorder comprises sleepapnea.
 5. The apparatus of claim 1, wherein the electrical impedancecomprises a near-field impedance and the physiological characteristiccomprises one or more of soft tissue crowding, ionic composition ofsaliva, or ionic composition of oral mucosa.
 6. The apparatus of claim1, wherein the electrical impedance comprises a far-field impedance andthe physiological characteristic comprises one or more of lung fluidlevel or airway length.
 7. The apparatus of claim 1, wherein the one ormore processors are configured to measure the electrical impedance bymeasuring a waveform in response to an electrical signal transmittedfrom an electrode of the plurality of the electrodes.
 8. The apparatusof claim 1, wherein the plurality of electrodes comprises a firstelectrode positioned near a left side of the patient's intraoral cavityand a second electrode positioned near a right side of the patient'sintraoral cavity when the intraoral appliance is worn by the patient. 9.The apparatus of claim 1, wherein the plurality of electrodes comprisesa first electrode positioned on an upper jaw of the patient and a secondelectrode positioned on a lower jaw of the patient when the intraoralappliance is worn by the patient.
 10. The apparatus of claim 1, whereinthe intraoral appliance comprises a first shell shaped to receive teethof the upper jaw and a second shell shaped to receive teeth of the lowerjaw, and wherein the first electrode is coupled to the first shell andthe second electrode is coupled to the second shell.
 11. The apparatusof claim 1, wherein the one or more processors are disposed on or withinthe intraoral appliance.
 12. The apparatus of claim 1, wherein theintraoral appliance comprises a polymeric shell having a plurality ofteeth-receiving cavities.
 13. An apparatus for monitoring aphysiological characteristic of a patient's airway, the apparatuscomprising: an intraoral appliance shaped to receive the patient's teethand comprising a plurality of electrodes each positioned to makeelectrical contact with the patient's intraoral cavity when theintraoral appliance is worn by the patient; and one or more processorsconfigured to: measure a far-field electrical impedance using theplurality of electrodes, and determine, based on the far-fieldelectrical impedance, one or more of: airway diameter, airway volume,airway resistance, lung fluid level, and breathing rate.
 14. A methodfor monitoring a physiological characteristic of a patient, the methodcomprising: positioning an intraoral appliance in the patient'sintraoral cavity, the intraoral appliance shaped to receive thepatient's teeth and comprising a plurality of electrodes each positionedto make electrical contact with a different part of the patient'sintraoral cavity; measuring an electrical impedance using the pluralityof electrodes; and determining the physiological characteristic based onthe electrical impedance.
 15. The method of claim 14, wherein thephysiological characteristic comprises one or more of: airway diameter,airway volume, airway resistance, lung fluid level, soft tissuecrowding, breathing rate, muscle activity, ionic composition of saliva,or ionic composition of oral mucosa.
 16. The method of claim 14, whereinthe physiological characteristic is related to a sleep disorder of thepatient, the sleep disorder comprising one or more of sleep apnea,snoring, or bruxism.
 17. The method of claim 14, wherein the signalcomprises an electrical impedance.
 18. The method of claim 17, whereinthe electrical impedance comprises a near-field impedance and thephysiological characteristic comprises one or more of soft tissuecrowding, ionic composition of saliva, or ionic composition of oralmucosa.
 19. The method of claim 17, wherein the electrical impedancecomprises a far-field impedance and the physiological characteristiccomprises one or more of lung fluid level or airway length.
 20. Themethod of claim 14, wherein the intraoral appliance comprises apolymeric shell having a plurality of teeth-receiving cavities.